Guard ruby/spec with spec/mspec/tool/wrap_with_guard.rb

164 files changed, 4393 insertions, 3901 deletions

diff --git a/spec/ruby/library/matrix/I_spec.rb b/spec/ruby/library/matrix/I_spec.rb
index 6eeffe8e98..aa064ed54b 100644
--- a/spec/ruby/library/matrix/I_spec.rb
+++ b/spec/ruby/library/matrix/I_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/identity'
 
-describe "Matrix.I" do
-  it_behaves_like :matrix_identity, :I
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/identity'
+
+  describe "Matrix.I" do
+    it_behaves_like :matrix_identity, :I
+  end
 end
diff --git a/spec/ruby/library/matrix/antisymmetric_spec.rb b/spec/ruby/library/matrix/antisymmetric_spec.rb
index 3eb0f8b726..a0d1a5f69b 100644
--- a/spec/ruby/library/matrix/antisymmetric_spec.rb
+++ b/spec/ruby/library/matrix/antisymmetric_spec.rb
@@ -1,36 +1,39 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-ruby_version_is "2.6" do
-  describe "Matrix#antisymmetric?" do
-    it "returns true for an antisymmetric Matrix" do
-      Matrix[[0, -2, Complex(1, 3)], [2, 0, 5], [-Complex(1, 3), -5, 0]].antisymmetric?.should be_true
-    end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-    it "returns true for a 0x0 empty matrix" do
-      Matrix.empty.antisymmetric?.should be_true
-    end
+  ruby_version_is "2.6" do
+    describe "Matrix#antisymmetric?" do
+      it "returns true for an antisymmetric Matrix" do
+        Matrix[[0, -2, Complex(1, 3)], [2, 0, 5], [-Complex(1, 3), -5, 0]].antisymmetric?.should be_true
+      end
 
-    it "returns false for non-antisymmetric matrices" do
-      [
-        Matrix[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
-        Matrix[[1, -2, 3], [2, 0, 6], [-3, -6, 0]],  # wrong diagonal element
-        Matrix[[0, 2, -3], [2, 0, 6], [-3, 6, 0]]    # only signs wrong
-      ].each do |matrix|
-        matrix.antisymmetric?.should be_false
+      it "returns true for a 0x0 empty matrix" do
+        Matrix.empty.antisymmetric?.should be_true
+      end
+
+      it "returns false for non-antisymmetric matrices" do
+        [
+          Matrix[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
+          Matrix[[1, -2, 3], [2, 0, 6], [-3, -6, 0]],  # wrong diagonal element
+          Matrix[[0, 2, -3], [2, 0, 6], [-3, 6, 0]]    # only signs wrong
+        ].each do |matrix|
+          matrix.antisymmetric?.should be_false
+        end
       end
-    end
 
-    it "raises an error for rectangular matrices" do
-      [
-        Matrix[[0], [0]],
-        Matrix[[0, 0]],
-        Matrix.empty(0, 2),
-        Matrix.empty(2, 0),
-      ].each do |rectangular_matrix|
-        -> {
-          rectangular_matrix.antisymmetric?
-        }.should raise_error(Matrix::ErrDimensionMismatch)
+      it "raises an error for rectangular matrices" do
+        [
+          Matrix[[0], [0]],
+          Matrix[[0, 0]],
+          Matrix.empty(0, 2),
+          Matrix.empty(2, 0),
+        ].each do |rectangular_matrix|
+          -> {
+            rectangular_matrix.antisymmetric?
+          }.should raise_error(Matrix::ErrDimensionMismatch)
+        end
       end
     end
   end
diff --git a/spec/ruby/library/matrix/build_spec.rb b/spec/ruby/library/matrix/build_spec.rb
index 6d8017a3df..d3055a1aa7 100644
--- a/spec/ruby/library/matrix/build_spec.rb
+++ b/spec/ruby/library/matrix/build_spec.rb
@@ -1,73 +1,76 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.build" do
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns a Matrix object of the given size" do
-    m = Matrix.build(3, 4){1}
-    m.should be_an_instance_of(Matrix)
-    m.row_size.should == 3
-    m.column_size.should == 4
-  end
+  describe "Matrix.build" do
 
-  it "builds the Matrix using the given block" do
-    Matrix.build(2, 3){|col, row| 10*col - row}.should ==
-      Matrix[[0, -1, -2], [10, 9, 8]]
-  end
+    it "returns a Matrix object of the given size" do
+      m = Matrix.build(3, 4){1}
+      m.should be_an_instance_of(Matrix)
+      m.row_size.should == 3
+      m.column_size.should == 4
+    end
 
-  it "iterates through the first row, then the second, ..." do
-    acc = []
-    Matrix.build(2, 3){|*args| acc << args}
-    acc.should == [[0, 0], [0, 1], [0, 2], [1, 0], [1, 1], [1, 2]]
-  end
+    it "builds the Matrix using the given block" do
+      Matrix.build(2, 3){|col, row| 10*col - row}.should ==
+        Matrix[[0, -1, -2], [10, 9, 8]]
+    end
 
-  it "returns an Enumerator is no block is given" do
-    enum = Matrix.build(2, 1)
-    enum.should be_an_instance_of(Enumerator)
-    enum.each{1}.should == Matrix[[1], [1]]
-  end
+    it "iterates through the first row, then the second, ..." do
+      acc = []
+      Matrix.build(2, 3){|*args| acc << args}
+      acc.should == [[0, 0], [0, 1], [0, 2], [1, 0], [1, 1], [1, 2]]
+    end
 
-  it "requires integers as parameters" do
-    -> { Matrix.build("1", "2"){1} }.should raise_error(TypeError)
-    -> { Matrix.build(nil, nil){1} }.should raise_error(TypeError)
-    -> { Matrix.build(1..2){1} }.should raise_error(TypeError)
-  end
+    it "returns an Enumerator is no block is given" do
+      enum = Matrix.build(2, 1)
+      enum.should be_an_instance_of(Enumerator)
+      enum.each{1}.should == Matrix[[1], [1]]
+    end
 
-  it "requires non-negative integers" do
-    -> { Matrix.build(-1, 1){1} }.should raise_error(ArgumentError)
-    -> { Matrix.build(+1,-1){1} }.should raise_error(ArgumentError)
-  end
+    it "requires integers as parameters" do
+      -> { Matrix.build("1", "2"){1} }.should raise_error(TypeError)
+      -> { Matrix.build(nil, nil){1} }.should raise_error(TypeError)
+      -> { Matrix.build(1..2){1} }.should raise_error(TypeError)
+    end
 
-  it "returns empty Matrix if one argument is zero" do
-    m = Matrix.build(0, 3){
-      raise "Should not yield"
-    }
-    m.should be_empty
-    m.column_size.should == 3
+    it "requires non-negative integers" do
+      -> { Matrix.build(-1, 1){1} }.should raise_error(ArgumentError)
+      -> { Matrix.build(+1,-1){1} }.should raise_error(ArgumentError)
+    end
 
-    m = Matrix.build(3, 0){
-      raise "Should not yield"
-    }
-    m.should be_empty
-    m.row_size.should == 3
-  end
+    it "returns empty Matrix if one argument is zero" do
+      m = Matrix.build(0, 3){
+        raise "Should not yield"
+      }
+      m.should be_empty
+      m.column_size.should == 3
 
-  it "tries to calls :to_int on arguments" do
-    int = mock('int')
-    int.should_receive(:to_int).twice.and_return(2)
-    Matrix.build(int, int){ 1 }.should == Matrix[ [1,1], [1,1] ]
-  end
+      m = Matrix.build(3, 0){
+        raise "Should not yield"
+      }
+      m.should be_empty
+      m.row_size.should == 3
+    end
 
-  it "builds an nxn Matrix when given only one argument" do
-    m = Matrix.build(3){1}
-    m.row_size.should == 3
-    m.column_size.should == 3
+    it "tries to calls :to_int on arguments" do
+      int = mock('int')
+      int.should_receive(:to_int).twice.and_return(2)
+      Matrix.build(int, int){ 1 }.should == Matrix[ [1,1], [1,1] ]
+    end
+
+    it "builds an nxn Matrix when given only one argument" do
+      m = Matrix.build(3){1}
+      m.row_size.should == 3
+      m.column_size.should == 3
+    end
   end
-end
 
-describe "for a subclass of Matrix" do
-  it "returns an instance of that subclass" do
-    MatrixSub.build(3){1}.should be_an_instance_of(MatrixSub)
+  describe "for a subclass of Matrix" do
+    it "returns an instance of that subclass" do
+      MatrixSub.build(3){1}.should be_an_instance_of(MatrixSub)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/clone_spec.rb b/spec/ruby/library/matrix/clone_spec.rb
index 74e5bf157e..bde119988f 100644
--- a/spec/ruby/library/matrix/clone_spec.rb
+++ b/spec/ruby/library/matrix/clone_spec.rb
@@ -1,25 +1,28 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#clone" do
-  before :each do
-    @a = Matrix[[1, 2], [3, 4], [5, 6]]
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns a shallow copy of the matrix" do
-    b = @a.clone
-    @a.should_not equal(b)
-    b.should be_kind_of(Matrix)
-    b.should == @a
-    0.upto(@a.row_size - 1) do |i|
-      @a.row(i).should_not equal(b.row(i))
+  describe "Matrix#clone" do
+    before :each do
+      @a = Matrix[[1, 2], [3, 4], [5, 6]]
+    end
+
+    it "returns a shallow copy of the matrix" do
+      b = @a.clone
+      @a.should_not equal(b)
+      b.should be_kind_of(Matrix)
+      b.should == @a
+      0.upto(@a.row_size - 1) do |i|
+        @a.row(i).should_not equal(b.row(i))
+      end
     end
-  end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.ins.clone.should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.ins.clone.should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/coerce_spec.rb b/spec/ruby/library/matrix/coerce_spec.rb
index 4022f00236..aa3a32765a 100644
--- a/spec/ruby/library/matrix/coerce_spec.rb
+++ b/spec/ruby/library/matrix/coerce_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#coerce" do
-  it "allows the division of integer by a Matrix " do
-    (1/Matrix[[0,1],[-1,0]]).should == Matrix[[0,-1],[1,0]]
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix#coerce" do
+    it "allows the division of integer by a Matrix " do
+      (1/Matrix[[0,1],[-1,0]]).should == Matrix[[0,-1],[1,0]]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/collect_spec.rb b/spec/ruby/library/matrix/collect_spec.rb
index bba640213b..66ec3486c8 100644
--- a/spec/ruby/library/matrix/collect_spec.rb
+++ b/spec/ruby/library/matrix/collect_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/collect'
 
-describe "Matrix#collect" do
-  it_behaves_like :collect, :collect
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/collect'
+
+  describe "Matrix#collect" do
+    it_behaves_like :collect, :collect
+  end
 end
diff --git a/spec/ruby/library/matrix/column_size_spec.rb b/spec/ruby/library/matrix/column_size_spec.rb
index 041914e5b9..e7b42b101e 100644
--- a/spec/ruby/library/matrix/column_size_spec.rb
+++ b/spec/ruby/library/matrix/column_size_spec.rb
@@ -1,13 +1,16 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#column_size" do
-  it "returns the number of columns" do
-    Matrix[ [1,2], [3,4] ].column_size.should == 2
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix#column_size" do
+    it "returns the number of columns" do
+      Matrix[ [1,2], [3,4] ].column_size.should == 2
+    end
 
-  it "returns 0 for empty matrices" do
-    Matrix[ [], [] ].column_size.should == 0
-    Matrix[ ].column_size.should == 0
+    it "returns 0 for empty matrices" do
+      Matrix[ [], [] ].column_size.should == 0
+      Matrix[ ].column_size.should == 0
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/column_spec.rb b/spec/ruby/library/matrix/column_spec.rb
index 1f3c80964a..98a767ad08 100644
--- a/spec/ruby/library/matrix/column_spec.rb
+++ b/spec/ruby/library/matrix/column_spec.rb
@@ -1,35 +1,38 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#column" do
-  before :all do
-    @m =  Matrix[[1,2,3], [2,3,4]]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns a Vector when called without a block" do
-    @m.column(1).should == Vector[2,3]
-  end
+  describe "Matrix#column" do
+    before :all do
+      @m =  Matrix[[1,2,3], [2,3,4]]
+    end
 
-  it "yields each element in the column to the block" do
-    a = []
-    @m.column(1) {|n| a << n }
-    a.should == [2,3]
-  end
+    it "returns a Vector when called without a block" do
+      @m.column(1).should == Vector[2,3]
+    end
 
-  it "counts backwards for negative argument" do
-    @m.column(-1).should == Vector[3, 4]
-  end
+    it "yields each element in the column to the block" do
+      a = []
+      @m.column(1) {|n| a << n }
+      a.should == [2,3]
+    end
 
-  it "returns self when called with a block" do
-    @m.column(0) { |x| x }.should equal(@m)
-  end
+    it "counts backwards for negative argument" do
+      @m.column(-1).should == Vector[3, 4]
+    end
 
-  it "returns nil when out of bounds" do
-    @m.column(3).should == nil
-  end
+    it "returns self when called with a block" do
+      @m.column(0) { |x| x }.should equal(@m)
+    end
+
+    it "returns nil when out of bounds" do
+      @m.column(3).should == nil
+    end
 
-  it "never yields when out of bounds" do
-    -> { @m.column(3){ raise } }.should_not raise_error
-    -> { @m.column(-4){ raise } }.should_not raise_error
+    it "never yields when out of bounds" do
+      -> { @m.column(3){ raise } }.should_not raise_error
+      -> { @m.column(-4){ raise } }.should_not raise_error
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/column_vector_spec.rb b/spec/ruby/library/matrix/column_vector_spec.rb
index 47e866a8d5..afdeaced47 100644
--- a/spec/ruby/library/matrix/column_vector_spec.rb
+++ b/spec/ruby/library/matrix/column_vector_spec.rb
@@ -1,25 +1,28 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.column_vector" do
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns a single column Matrix when called with an Array" do
-    m = Matrix.column_vector([4,5,6])
-    m.should be_an_instance_of(Matrix)
-    m.should == Matrix[ [4],[5],[6] ]
-  end
+  describe "Matrix.column_vector" do
 
-  it "returns an empty Matrix when called with an empty Array" do
-    m = Matrix.column_vector([])
-    m.should be_an_instance_of(Matrix)
-    m.row_size.should == 0
-    m.column_size.should == 1
-  end
+    it "returns a single column Matrix when called with an Array" do
+      m = Matrix.column_vector([4,5,6])
+      m.should be_an_instance_of(Matrix)
+      m.should == Matrix[ [4],[5],[6] ]
+    end
+
+    it "returns an empty Matrix when called with an empty Array" do
+      m = Matrix.column_vector([])
+      m.should be_an_instance_of(Matrix)
+      m.row_size.should == 0
+      m.column_size.should == 1
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.column_vector([4,5,6]).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.column_vector([4,5,6]).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/column_vectors_spec.rb b/spec/ruby/library/matrix/column_vectors_spec.rb
index b0cb6f914c..7bec095b9a 100644
--- a/spec/ruby/library/matrix/column_vectors_spec.rb
+++ b/spec/ruby/library/matrix/column_vectors_spec.rb
@@ -1,26 +1,29 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#column_vectors" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  before :each do
-    @vectors = Matrix[ [1,2], [3,4] ].column_vectors
-  end
+  describe "Matrix#column_vectors" do
 
-  it "returns an Array" do
-    Matrix[ [1,2], [3,4] ].column_vectors.should be_an_instance_of(Array)
-  end
+    before :each do
+      @vectors = Matrix[ [1,2], [3,4] ].column_vectors
+    end
 
-  it "returns an Array of Vectors" do
-    @vectors.all? {|v| v.should be_an_instance_of(Vector)}
-  end
+    it "returns an Array" do
+      Matrix[ [1,2], [3,4] ].column_vectors.should be_an_instance_of(Array)
+    end
 
-  it "returns each column as a Vector" do
-    @vectors.should == [Vector[1,3], Vector[2,4]]
-  end
+    it "returns an Array of Vectors" do
+      @vectors.all? {|v| v.should be_an_instance_of(Vector)}
+    end
 
-  it "returns an empty Array for empty matrices" do
-    Matrix[ [] ].column_vectors.should == []
-  end
+    it "returns each column as a Vector" do
+      @vectors.should == [Vector[1,3], Vector[2,4]]
+    end
+
+    it "returns an empty Array for empty matrices" do
+      Matrix[ [] ].column_vectors.should == []
+    end
 
+  end
 end
diff --git a/spec/ruby/library/matrix/columns_spec.rb b/spec/ruby/library/matrix/columns_spec.rb
index 3095fdd7af..757086c14b 100644
--- a/spec/ruby/library/matrix/columns_spec.rb
+++ b/spec/ruby/library/matrix/columns_spec.rb
@@ -1,42 +1,45 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.columns" do
-  before :each do
-    @a = [1, 2]
-    @b = [3, 4]
-    @m = Matrix.columns([@a, @b])
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "creates a Matrix from argument columns" do
-    @m.should be_an_instance_of(Matrix)
-    @m.column(0).to_a.should == @a
-    @m.column(1).to_a.should == @b
-  end
+  describe "Matrix.columns" do
+    before :each do
+      @a = [1, 2]
+      @b = [3, 4]
+      @m = Matrix.columns([@a, @b])
+    end
 
-  it "accepts Vectors as argument columns" do
-    m = Matrix.columns([Vector[*@a], Vector[*@b]])
-    m.should == @m
-    m.column(0).to_a.should == @a
-    m.column(1).to_a.should == @b
-  end
+    it "creates a Matrix from argument columns" do
+      @m.should be_an_instance_of(Matrix)
+      @m.column(0).to_a.should == @a
+      @m.column(1).to_a.should == @b
+    end
 
-  it "handles empty matrices" do
-    e = Matrix.columns([])
-    e.row_size.should == 0
-    e.column_size.should == 0
-    e.should == Matrix[]
+    it "accepts Vectors as argument columns" do
+      m = Matrix.columns([Vector[*@a], Vector[*@b]])
+      m.should == @m
+      m.column(0).to_a.should == @a
+      m.column(1).to_a.should == @b
+    end
 
-    v = Matrix.columns([[],[],[]])
-    v.row_size.should == 0
-    v.column_size.should == 3
-    v.should == Matrix[[], [], []].transpose
-  end
+    it "handles empty matrices" do
+      e = Matrix.columns([])
+      e.row_size.should == 0
+      e.column_size.should == 0
+      e.should == Matrix[]
+
+      v = Matrix.columns([[],[],[]])
+      v.row_size.should == 0
+      v.column_size.should == 3
+      v.should == Matrix[[], [], []].transpose
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.columns([[1]]).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.columns([[1]]).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/conj_spec.rb b/spec/ruby/library/matrix/conj_spec.rb
index ecee95c255..a922580399 100644
--- a/spec/ruby/library/matrix/conj_spec.rb
+++ b/spec/ruby/library/matrix/conj_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/conjugate'
 
-describe "Matrix#conj" do
-  it_behaves_like :matrix_conjugate, :conj
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/conjugate'
+
+  describe "Matrix#conj" do
+    it_behaves_like :matrix_conjugate, :conj
+  end
 end
diff --git a/spec/ruby/library/matrix/conjugate_spec.rb b/spec/ruby/library/matrix/conjugate_spec.rb
index 682bd41d94..b99792a24b 100644
--- a/spec/ruby/library/matrix/conjugate_spec.rb
+++ b/spec/ruby/library/matrix/conjugate_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/conjugate'
 
-describe "Matrix#conjugate" do
-  it_behaves_like :matrix_conjugate, :conjugate
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/conjugate'
+
+  describe "Matrix#conjugate" do
+    it_behaves_like :matrix_conjugate, :conjugate
+  end
 end
diff --git a/spec/ruby/library/matrix/constructor_spec.rb b/spec/ruby/library/matrix/constructor_spec.rb
index 70d77babbb..d8224b4430 100644
--- a/spec/ruby/library/matrix/constructor_spec.rb
+++ b/spec/ruby/library/matrix/constructor_spec.rb
@@ -1,65 +1,68 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.[]" do
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "requires arrays as parameters" do
-    -> { Matrix[5] }.should raise_error(TypeError)
-    -> { Matrix[nil] }.should raise_error(TypeError)
-    -> { Matrix[1..2] }.should raise_error(TypeError)
-    -> { Matrix[[1, 2], 3] }.should raise_error(TypeError)
-  end
+  describe "Matrix.[]" do
 
-  it "creates an empty Matrix with no arguments" do
-    m = Matrix[]
-    m.column_size.should == 0
-    m.row_size.should == 0
-  end
+    it "requires arrays as parameters" do
+      -> { Matrix[5] }.should raise_error(TypeError)
+      -> { Matrix[nil] }.should raise_error(TypeError)
+      -> { Matrix[1..2] }.should raise_error(TypeError)
+      -> { Matrix[[1, 2], 3] }.should raise_error(TypeError)
+    end
 
-  it "raises for non-rectangular matrices" do
-    ->{ Matrix[ [0], [0,1] ] }.should \
-      raise_error(Matrix::ErrDimensionMismatch)
-    ->{ Matrix[ [0,1], [0,1,2], [0,1] ]}.should \
-      raise_error(Matrix::ErrDimensionMismatch)
-  end
+    it "creates an empty Matrix with no arguments" do
+      m = Matrix[]
+      m.column_size.should == 0
+      m.row_size.should == 0
+    end
 
-  it "accepts vector arguments" do
-    a = Matrix[Vector[1, 2], Vector[3, 4]]
-    a.should be_an_instance_of(Matrix)
-    a.should == Matrix[ [1, 2], [3, 4] ]
-  end
+    it "raises for non-rectangular matrices" do
+      ->{ Matrix[ [0], [0,1] ] }.should \
+        raise_error(Matrix::ErrDimensionMismatch)
+      ->{ Matrix[ [0,1], [0,1,2], [0,1] ]}.should \
+        raise_error(Matrix::ErrDimensionMismatch)
+    end
 
-  it "tries to calls :to_ary on arguments" do
-    array = mock('ary')
-    array.should_receive(:to_ary).and_return([1,2])
-    Matrix[array, [3,4] ].should == Matrix[ [1,2], [3,4] ]
-  end
+    it "accepts vector arguments" do
+      a = Matrix[Vector[1, 2], Vector[3, 4]]
+      a.should be_an_instance_of(Matrix)
+      a.should == Matrix[ [1, 2], [3, 4] ]
+    end
 
+    it "tries to calls :to_ary on arguments" do
+      array = mock('ary')
+      array.should_receive(:to_ary).and_return([1,2])
+      Matrix[array, [3,4] ].should == Matrix[ [1,2], [3,4] ]
+    end
 
-  it "returns a Matrix object" do
-    Matrix[ [1] ].should be_an_instance_of(Matrix)
-  end
 
-  it "can create an nxn Matrix" do
-    m = Matrix[ [20,30], [40.5, 9] ]
-    m.row_size.should == 2
-    m.column_size.should == 2
-    m.column(0).should == Vector[20, 40.5]
-    m.column(1).should == Vector[30, 9]
-    m.row(0).should == Vector[20, 30]
-    m.row(1).should == Vector[40.5, 9]
-  end
+    it "returns a Matrix object" do
+      Matrix[ [1] ].should be_an_instance_of(Matrix)
+    end
 
-  it "can create a 0xn Matrix" do
-    m = Matrix[ [], [], [] ]
-    m.row_size.should == 3
-    m.column_size.should == 0
-  end
+    it "can create an nxn Matrix" do
+      m = Matrix[ [20,30], [40.5, 9] ]
+      m.row_size.should == 2
+      m.column_size.should == 2
+      m.column(0).should == Vector[20, 40.5]
+      m.column(1).should == Vector[30, 9]
+      m.row(0).should == Vector[20, 30]
+      m.row(1).should == Vector[40.5, 9]
+    end
+
+    it "can create a 0xn Matrix" do
+      m = Matrix[ [], [], [] ]
+      m.row_size.should == 3
+      m.column_size.should == 0
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub[ [20,30], [40.5, 9] ].should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub[ [20,30], [40.5, 9] ].should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/det_spec.rb b/spec/ruby/library/matrix/det_spec.rb
index aa7086cacf..7d3d547735 100644
--- a/spec/ruby/library/matrix/det_spec.rb
+++ b/spec/ruby/library/matrix/det_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'shared/determinant'
-require 'matrix'
 
-describe "Matrix#det" do
-  it_behaves_like :determinant, :det
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/determinant'
+  require 'matrix'
+
+  describe "Matrix#det" do
+    it_behaves_like :determinant, :det
+  end
 end
diff --git a/spec/ruby/library/matrix/determinant_spec.rb b/spec/ruby/library/matrix/determinant_spec.rb
index 825c9907b1..bfd91fcf68 100644
--- a/spec/ruby/library/matrix/determinant_spec.rb
+++ b/spec/ruby/library/matrix/determinant_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'shared/determinant'
-require 'matrix'
 
-describe "Matrix#determinant" do
-  it_behaves_like :determinant, :determinant
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/determinant'
+  require 'matrix'
+
+  describe "Matrix#determinant" do
+    it_behaves_like :determinant, :determinant
+  end
 end
diff --git a/spec/ruby/library/matrix/diagonal_spec.rb b/spec/ruby/library/matrix/diagonal_spec.rb
index ef9738e73e..8c82433fde 100644
--- a/spec/ruby/library/matrix/diagonal_spec.rb
+++ b/spec/ruby/library/matrix/diagonal_spec.rb
@@ -1,72 +1,75 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.diagonal" do
-  before :each do
-    @m = Matrix.diagonal(10, 11, 12, 13, 14)
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns an object of type Matrix" do
-    @m.should be_kind_of(Matrix)
-  end
+  describe "Matrix.diagonal" do
+    before :each do
+      @m = Matrix.diagonal(10, 11, 12, 13, 14)
+    end
 
-  it "returns a square Matrix of the right size" do
-    @m.column_size.should == 5
-    @m.row_size.should == 5
-  end
+    it "returns an object of type Matrix" do
+      @m.should be_kind_of(Matrix)
+    end
 
-  it "sets the diagonal to the arguments" do
-    (0..4).each do |i|
-      @m[i, i].should == i + 10
+    it "returns a square Matrix of the right size" do
+      @m.column_size.should == 5
+      @m.row_size.should == 5
     end
-  end
 
-  it "fills all non-diagonal cells with 0" do
-    (0..4).each do |i|
-      (0..4).each do |j|
-        if i != j
-          @m[i, j].should == 0
+    it "sets the diagonal to the arguments" do
+      (0..4).each do |i|
+        @m[i, i].should == i + 10
+      end
+    end
+
+    it "fills all non-diagonal cells with 0" do
+      (0..4).each do |i|
+        (0..4).each do |j|
+          if i != j
+            @m[i, j].should == 0
+          end
         end
       end
     end
-  end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.diagonal(1).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.diagonal(1).should be_an_instance_of(MatrixSub)
+      end
     end
   end
-end
 
-describe "Matrix.diagonal?" do
-  it "returns true for a diagonal Matrix" do
-    Matrix.diagonal([1, 2, 3]).diagonal?.should be_true
-  end
+  describe "Matrix.diagonal?" do
+    it "returns true for a diagonal Matrix" do
+      Matrix.diagonal([1, 2, 3]).diagonal?.should be_true
+    end
 
-  it "returns true for a zero square Matrix" do
-    Matrix.zero(3).diagonal?.should be_true
-  end
+    it "returns true for a zero square Matrix" do
+      Matrix.zero(3).diagonal?.should be_true
+    end
 
-  it "returns false for a non diagonal square Matrix" do
-    Matrix[[0, 1], [0, 0]].diagonal?.should be_false
-    Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].diagonal?.should be_false
-  end
+    it "returns false for a non diagonal square Matrix" do
+      Matrix[[0, 1], [0, 0]].diagonal?.should be_false
+      Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].diagonal?.should be_false
+    end
 
-  it "returns true for an empty 0x0 matrix" do
-    Matrix.empty(0,0).diagonal?.should be_true
-  end
+    it "returns true for an empty 0x0 matrix" do
+      Matrix.empty(0,0).diagonal?.should be_true
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.diagonal?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.diagonal?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/divide_spec.rb b/spec/ruby/library/matrix/divide_spec.rb
index 2e3bb85bf6..68e6f1fde5 100644
--- a/spec/ruby/library/matrix/divide_spec.rb
+++ b/spec/ruby/library/matrix/divide_spec.rb
@@ -1,54 +1,57 @@
 require_relative '../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
-
-describe "Matrix#/" do
-  before :each do
-    @a = Matrix[ [1, 2], [3, 4] ]
-    @b = Matrix[ [4, 5], [6, 7] ]
-    @c = Matrix[ [1.2, 2.4], [3.6, 4.8] ]
-  end
 
-  it "returns the result of dividing self by another Matrix" do
-    (@a / @b).should be_close_to_matrix([[2.5, -1.5], [1.5, -0.5]])
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  # Guard against the Mathn library
-  guard -> { !defined?(Math.rsqrt) } do
-    it "returns the result of dividing self by a Fixnum" do
-      (@a / 2).should == Matrix[ [0, 1], [1, 2] ]
+  describe "Matrix#/" do
+    before :each do
+      @a = Matrix[ [1, 2], [3, 4] ]
+      @b = Matrix[ [4, 5], [6, 7] ]
+      @c = Matrix[ [1.2, 2.4], [3.6, 4.8] ]
     end
 
-    it "returns the result of dividing self by a Bignum" do
-      (@a / bignum_value).should == Matrix[ [0, 0], [0, 0] ]
+    it "returns the result of dividing self by another Matrix" do
+      (@a / @b).should be_close_to_matrix([[2.5, -1.5], [1.5, -0.5]])
     end
-  end
 
-  it "returns the result of dividing self by a Float" do
-    (@c / 1.2).should == Matrix[ [1, 2], [3, 4] ]
-  end
+    # Guard against the Mathn library
+    guard -> { !defined?(Math.rsqrt) } do
+      it "returns the result of dividing self by a Fixnum" do
+        (@a / 2).should == Matrix[ [0, 1], [1, 2] ]
+      end
 
-  it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
-    -> { @a / Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
-  end
+      it "returns the result of dividing self by a Bignum" do
+        (@a / bignum_value).should == Matrix[ [0, 0], [0, 0] ]
+      end
+    end
 
-  it "returns an instance of Matrix" do
-    (@a / @b).should be_kind_of(Matrix)
-  end
+    it "returns the result of dividing self by a Float" do
+      (@c / 1.2).should == Matrix[ [1, 2], [3, 4] ]
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      m = MatrixSub.ins
-      (m/m).should be_an_instance_of(MatrixSub)
-      (m/1).should be_an_instance_of(MatrixSub)
+    it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
+      -> { @a / Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
+
+    it "returns an instance of Matrix" do
+      (@a / @b).should be_kind_of(Matrix)
     end
-  end
 
-  it "raises a TypeError if other is of wrong type" do
-    -> { @a / nil        }.should raise_error(TypeError)
-    -> { @a / "a"        }.should raise_error(TypeError)
-    -> { @a / [ [1, 2] ] }.should raise_error(TypeError)
-    -> { @a / Object.new }.should raise_error(TypeError)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        m = MatrixSub.ins
+        (m/m).should be_an_instance_of(MatrixSub)
+        (m/1).should be_an_instance_of(MatrixSub)
+      end
+    end
+
+    it "raises a TypeError if other is of wrong type" do
+      -> { @a / nil        }.should raise_error(TypeError)
+      -> { @a / "a"        }.should raise_error(TypeError)
+      -> { @a / [ [1, 2] ] }.should raise_error(TypeError)
+      -> { @a / Object.new }.should raise_error(TypeError)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/each_spec.rb b/spec/ruby/library/matrix/each_spec.rb
index f3b0f01867..d2b13c80b6 100644
--- a/spec/ruby/library/matrix/each_spec.rb
+++ b/spec/ruby/library/matrix/each_spec.rb
@@ -1,74 +1,77 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#each" do
-  before :all do
-    @m = Matrix[ [1, 2, 3], [4, 5, 6] ]
-    @result = (1..6).to_a
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an Enumerator when called without a block" do
-    enum = @m.each
-    enum.should be_an_instance_of(Enumerator)
-    enum.to_a.should == @result
-  end
+  describe "Matrix#each" do
+    before :all do
+      @m = Matrix[ [1, 2, 3], [4, 5, 6] ]
+      @result = (1..6).to_a
+    end
 
-  it "returns self" do
-    @m.each{}.should equal(@m)
-  end
+    it "returns an Enumerator when called without a block" do
+      enum = @m.each
+      enum.should be_an_instance_of(Enumerator)
+      enum.to_a.should == @result
+    end
 
-  it "yields the elements starting with the those of the first row" do
-    a = []
-    @m.each {|x| a << x}
-    a.should ==  @result
-  end
-end
+    it "returns self" do
+      @m.each{}.should equal(@m)
+    end
 
-describe "Matrix#each with an argument" do
-  before :all do
-    @m = Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ]
-    @t = Matrix[ [1, 2], [3, 4], [5, 6], [7, 8] ]
+    it "yields the elements starting with the those of the first row" do
+      a = []
+      @m.each {|x| a << x}
+      a.should ==  @result
+    end
   end
 
-  it "raises an ArgumentError for unrecognized argument" do
-    -> {
-      @m.each("all"){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.each(nil){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.each(:left){}
-    }.should raise_error(ArgumentError)
-  end
+  describe "Matrix#each with an argument" do
+    before :all do
+      @m = Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ]
+      @t = Matrix[ [1, 2], [3, 4], [5, 6], [7, 8] ]
+    end
 
-  it "yields the rights elements when passed :diagonal" do
-    @m.each(:diagonal).to_a.should == [1, 6]
-    @t.each(:diagonal).to_a.should == [1, 4]
-  end
+    it "raises an ArgumentError for unrecognized argument" do
+      -> {
+        @m.each("all"){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.each(nil){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.each(:left){}
+      }.should raise_error(ArgumentError)
+    end
 
-  it "yields the rights elements when passed :off_diagonal" do
-    @m.each(:off_diagonal).to_a.should == [2, 3, 4, 5, 7, 8]
-    @t.each(:off_diagonal).to_a.should == [2, 3, 5, 6, 7, 8]
-  end
+    it "yields the rights elements when passed :diagonal" do
+      @m.each(:diagonal).to_a.should == [1, 6]
+      @t.each(:diagonal).to_a.should == [1, 4]
+    end
 
-  it "yields the rights elements when passed :lower" do
-    @m.each(:lower).to_a.should == [1, 5, 6]
-    @t.each(:lower).to_a.should == [1, 3, 4, 5, 6, 7, 8]
-  end
+    it "yields the rights elements when passed :off_diagonal" do
+      @m.each(:off_diagonal).to_a.should == [2, 3, 4, 5, 7, 8]
+      @t.each(:off_diagonal).to_a.should == [2, 3, 5, 6, 7, 8]
+    end
 
-  it "yields the rights elements when passed :strict_lower" do
-    @m.each(:strict_lower).to_a.should == [5]
-    @t.each(:strict_lower).to_a.should == [3, 5, 6, 7, 8]
-  end
+    it "yields the rights elements when passed :lower" do
+      @m.each(:lower).to_a.should == [1, 5, 6]
+      @t.each(:lower).to_a.should == [1, 3, 4, 5, 6, 7, 8]
+    end
 
-  it "yields the rights elements when passed :strict_upper" do
-    @m.each(:strict_upper).to_a.should == [2, 3, 4, 7, 8]
-    @t.each(:strict_upper).to_a.should == [2]
-  end
+    it "yields the rights elements when passed :strict_lower" do
+      @m.each(:strict_lower).to_a.should == [5]
+      @t.each(:strict_lower).to_a.should == [3, 5, 6, 7, 8]
+    end
+
+    it "yields the rights elements when passed :strict_upper" do
+      @m.each(:strict_upper).to_a.should == [2, 3, 4, 7, 8]
+      @t.each(:strict_upper).to_a.should == [2]
+    end
 
-  it "yields the rights elements when passed :upper" do
-    @m.each(:upper).to_a.should == [1, 2, 3, 4, 6, 7, 8]
-    @t.each(:upper).to_a.should == [1, 2, 4]
+    it "yields the rights elements when passed :upper" do
+      @m.each(:upper).to_a.should == [1, 2, 3, 4, 6, 7, 8]
+      @t.each(:upper).to_a.should == [1, 2, 4]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/each_with_index_spec.rb b/spec/ruby/library/matrix/each_with_index_spec.rb
index a005b88621..59549f77b7 100644
--- a/spec/ruby/library/matrix/each_with_index_spec.rb
+++ b/spec/ruby/library/matrix/each_with_index_spec.rb
@@ -1,81 +1,84 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#each_with_index" do
-  before :all do
-    @m = Matrix[ [1, 2, 3], [4, 5, 6] ]
-    @result = [
-      [1, 0, 0],
-      [2, 0, 1],
-      [3, 0, 2],
-      [4, 1, 0],
-      [5, 1, 1],
-      [6, 1, 2]
-    ]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an Enumerator when called without a block" do
-    enum = @m.each_with_index
-    enum.should be_an_instance_of(Enumerator)
-    enum.to_a.should == @result
-  end
+  describe "Matrix#each_with_index" do
+    before :all do
+      @m = Matrix[ [1, 2, 3], [4, 5, 6] ]
+      @result = [
+        [1, 0, 0],
+        [2, 0, 1],
+        [3, 0, 2],
+        [4, 1, 0],
+        [5, 1, 1],
+        [6, 1, 2]
+      ]
+    end
 
-  it "returns self" do
-    @m.each_with_index{}.should equal(@m)
-  end
+    it "returns an Enumerator when called without a block" do
+      enum = @m.each_with_index
+      enum.should be_an_instance_of(Enumerator)
+      enum.to_a.should == @result
+    end
 
-  it "yields the elements starting with the those of the first row" do
-    a = []
-    @m.each_with_index {|x, r, c| a << [x, r, c]}
-    a.should == @result
-  end
-end
+    it "returns self" do
+      @m.each_with_index{}.should equal(@m)
+    end
 
-describe "Matrix#each_with_index with an argument" do
-  before :all do
-    @m = Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ]
-    @t = Matrix[ [1, 2], [3, 4], [5, 6], [7, 8] ]
+    it "yields the elements starting with the those of the first row" do
+      a = []
+      @m.each_with_index {|x, r, c| a << [x, r, c]}
+      a.should == @result
+    end
   end
 
-  it "raises an ArgumentError for unrecognized argument" do
-    -> {
-      @m.each_with_index("all"){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.each_with_index(nil){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.each_with_index(:left){}
-    }.should raise_error(ArgumentError)
-  end
+  describe "Matrix#each_with_index with an argument" do
+    before :all do
+      @m = Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ]
+      @t = Matrix[ [1, 2], [3, 4], [5, 6], [7, 8] ]
+    end
 
-  it "yields the rights elements when passed :diagonal" do
-    @m.each_with_index(:diagonal).to_a.should == [[1, 0, 0], [6, 1, 1]]
-    @t.each_with_index(:diagonal).to_a.should == [[1, 0, 0], [4, 1, 1]]
-  end
+    it "raises an ArgumentError for unrecognized argument" do
+      -> {
+        @m.each_with_index("all"){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.each_with_index(nil){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.each_with_index(:left){}
+      }.should raise_error(ArgumentError)
+    end
 
-  it "yields the rights elements when passed :off_diagonal" do
-    @m.each_with_index(:off_diagonal).to_a.should == [[2, 0, 1], [3, 0, 2], [4, 0, 3], [5, 1, 0], [7, 1, 2], [8, 1, 3]]
-    @t.each_with_index(:off_diagonal).to_a.should == [[2, 0, 1], [3, 1, 0], [5, 2, 0], [6, 2, 1], [7, 3, 0], [8, 3, 1]]
-  end
+    it "yields the rights elements when passed :diagonal" do
+      @m.each_with_index(:diagonal).to_a.should == [[1, 0, 0], [6, 1, 1]]
+      @t.each_with_index(:diagonal).to_a.should == [[1, 0, 0], [4, 1, 1]]
+    end
 
-  it "yields the rights elements when passed :lower" do
-    @m.each_with_index(:lower).to_a.should == [[1, 0, 0], [5, 1, 0], [6, 1, 1]]
-    @t.each_with_index(:lower).to_a.should == [[1, 0, 0], [3, 1, 0], [4, 1, 1], [5, 2, 0], [6, 2, 1], [7, 3, 0], [8, 3, 1]]
-  end
+    it "yields the rights elements when passed :off_diagonal" do
+      @m.each_with_index(:off_diagonal).to_a.should == [[2, 0, 1], [3, 0, 2], [4, 0, 3], [5, 1, 0], [7, 1, 2], [8, 1, 3]]
+      @t.each_with_index(:off_diagonal).to_a.should == [[2, 0, 1], [3, 1, 0], [5, 2, 0], [6, 2, 1], [7, 3, 0], [8, 3, 1]]
+    end
 
-  it "yields the rights elements when passed :strict_lower" do
-    @m.each_with_index(:strict_lower).to_a.should == [[5, 1, 0]]
-    @t.each_with_index(:strict_lower).to_a.should == [[3, 1, 0], [5, 2, 0], [6, 2, 1], [7, 3, 0], [8, 3, 1]]
-  end
+    it "yields the rights elements when passed :lower" do
+      @m.each_with_index(:lower).to_a.should == [[1, 0, 0], [5, 1, 0], [6, 1, 1]]
+      @t.each_with_index(:lower).to_a.should == [[1, 0, 0], [3, 1, 0], [4, 1, 1], [5, 2, 0], [6, 2, 1], [7, 3, 0], [8, 3, 1]]
+    end
 
-  it "yields the rights elements when passed :strict_upper" do
-    @m.each_with_index(:strict_upper).to_a.should == [[2, 0, 1], [3, 0, 2], [4, 0, 3], [7, 1, 2], [8, 1, 3]]
-    @t.each_with_index(:strict_upper).to_a.should == [[2, 0, 1]]
-  end
+    it "yields the rights elements when passed :strict_lower" do
+      @m.each_with_index(:strict_lower).to_a.should == [[5, 1, 0]]
+      @t.each_with_index(:strict_lower).to_a.should == [[3, 1, 0], [5, 2, 0], [6, 2, 1], [7, 3, 0], [8, 3, 1]]
+    end
+
+    it "yields the rights elements when passed :strict_upper" do
+      @m.each_with_index(:strict_upper).to_a.should == [[2, 0, 1], [3, 0, 2], [4, 0, 3], [7, 1, 2], [8, 1, 3]]
+      @t.each_with_index(:strict_upper).to_a.should == [[2, 0, 1]]
+    end
 
-  it "yields the rights elements when passed :upper" do
-    @m.each_with_index(:upper).to_a.should == [[1, 0, 0], [2, 0, 1], [3, 0, 2], [4, 0, 3], [6, 1, 1], [7, 1, 2], [8, 1, 3]]
-    @t.each_with_index(:upper).to_a.should == [[1, 0, 0], [2, 0, 1], [4, 1, 1]]
+    it "yields the rights elements when passed :upper" do
+      @m.each_with_index(:upper).to_a.should == [[1, 0, 0], [2, 0, 1], [3, 0, 2], [4, 0, 3], [6, 1, 1], [7, 1, 2], [8, 1, 3]]
+      @t.each_with_index(:upper).to_a.should == [[1, 0, 0], [2, 0, 1], [4, 1, 1]]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalue_matrix_spec.rb b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalue_matrix_spec.rb
index 67f9dd1c19..f9ffca0123 100644
--- a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalue_matrix_spec.rb
+++ b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalue_matrix_spec.rb
@@ -1,9 +1,12 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::EigenvalueDecomposition#eigenvalue_matrix" do
-  it "returns a diagonal matrix with the eigenvalues on the diagonal" do
-    Matrix[[14, 16], [-6, -6]].eigensystem.eigenvalue_matrix.should == Matrix[[6, 0],[0, 2]]
-    Matrix[[1, 1], [-1, 1]].eigensystem.eigenvalue_matrix.should == Matrix[[Complex(1,1), 0],[0, Complex(1,-1)]]
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::EigenvalueDecomposition#eigenvalue_matrix" do
+    it "returns a diagonal matrix with the eigenvalues on the diagonal" do
+      Matrix[[14, 16], [-6, -6]].eigensystem.eigenvalue_matrix.should == Matrix[[6, 0],[0, 2]]
+      Matrix[[1, 1], [-1, 1]].eigensystem.eigenvalue_matrix.should == Matrix[[Complex(1,1), 0],[0, Complex(1,-1)]]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalues_spec.rb b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalues_spec.rb
index 7552b7616c..650d43d90f 100644
--- a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalues_spec.rb
+++ b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvalues_spec.rb
@@ -1,22 +1,25 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::EigenvalueDecomposition#eigenvalues" do
-  it "returns an array of complex eigenvalues for a rotation matrix" do
-    Matrix[[ 1, 1],
-           [-1, 1]].eigensystem.eigenvalues.sort_by{|v| v.imag}.should ==
-    [ Complex(1, -1), Complex(1, 1)]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an array of real eigenvalues for a symmetric matrix" do
-    Matrix[[1, 2],
-           [2, 1]].eigensystem.eigenvalues.sort.map!{|x| x.round(10)}.should ==
-    [ -1, 3 ]
-  end
+  describe "Matrix::EigenvalueDecomposition#eigenvalues" do
+    it "returns an array of complex eigenvalues for a rotation matrix" do
+      Matrix[[ 1, 1],
+             [-1, 1]].eigensystem.eigenvalues.sort_by{|v| v.imag}.should ==
+      [ Complex(1, -1), Complex(1, 1)]
+    end
+
+    it "returns an array of real eigenvalues for a symmetric matrix" do
+      Matrix[[1, 2],
+             [2, 1]].eigensystem.eigenvalues.sort.map!{|x| x.round(10)}.should ==
+      [ -1, 3 ]
+    end
 
-  it "returns an array of real eigenvalues for a matrix" do
-    Matrix[[14, 16],
-           [-6, -6]].eigensystem.eigenvalues.sort.map!{|x| x.round(10)}.should ==
-    [ 2, 6 ]
+    it "returns an array of real eigenvalues for a matrix" do
+      Matrix[[14, 16],
+             [-6, -6]].eigensystem.eigenvalues.sort.map!{|x| x.round(10)}.should ==
+      [ 2, 6 ]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvector_matrix_spec.rb b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvector_matrix_spec.rb
index 09f229ee15..57299ce69e 100644
--- a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvector_matrix_spec.rb
+++ b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvector_matrix_spec.rb
@@ -1,20 +1,23 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::EigenvalueDecomposition#eigenvector_matrix" do
-  it "returns a complex eigenvector matrix given a rotation matrix" do
-    # Fix me: should test for linearity, not for equality
-    Matrix[[ 1, 1],
-           [-1, 1]].eigensystem.eigenvector_matrix.should ==
-    Matrix[[1, 1],
-           [Complex(0, 1), Complex(0, -1)]]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::EigenvalueDecomposition#eigenvector_matrix" do
+    it "returns a complex eigenvector matrix given a rotation matrix" do
+      # Fix me: should test for linearity, not for equality
+      Matrix[[ 1, 1],
+             [-1, 1]].eigensystem.eigenvector_matrix.should ==
+      Matrix[[1, 1],
+             [Complex(0, 1), Complex(0, -1)]]
+    end
 
-  it "returns an real eigenvector matrix for a symmetric matrix" do
-    # Fix me: should test for linearity, not for equality
-    Matrix[[1, 2],
-           [2, 1]].eigensystem.eigenvector_matrix.should ==
-    Matrix[[0.7071067811865475, 0.7071067811865475],
-           [-0.7071067811865475, 0.7071067811865475]]
+    it "returns an real eigenvector matrix for a symmetric matrix" do
+      # Fix me: should test for linearity, not for equality
+      Matrix[[1, 2],
+             [2, 1]].eigensystem.eigenvector_matrix.should ==
+      Matrix[[0.7071067811865475, 0.7071067811865475],
+             [-0.7071067811865475, 0.7071067811865475]]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvectors_spec.rb b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvectors_spec.rb
index 2b6ce74ea8..54e6857bf3 100644
--- a/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvectors_spec.rb
+++ b/spec/ruby/library/matrix/eigenvalue_decomposition/eigenvectors_spec.rb
@@ -1,22 +1,25 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::EigenvalueDecomposition#eigenvectors" do
-  it "returns an array of complex eigenvectors for a rotation matrix" do
-    # Fix me: should test for linearity, not for equality
-    Matrix[[ 1, 1],
-           [-1, 1]].eigensystem.eigenvectors.should ==
-    [ Vector[1, Complex(0, 1)],
-      Vector[1, Complex(0, -1)]
-    ]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::EigenvalueDecomposition#eigenvectors" do
+    it "returns an array of complex eigenvectors for a rotation matrix" do
+      # Fix me: should test for linearity, not for equality
+      Matrix[[ 1, 1],
+             [-1, 1]].eigensystem.eigenvectors.should ==
+      [ Vector[1, Complex(0, 1)],
+        Vector[1, Complex(0, -1)]
+      ]
+    end
 
-  it "returns an array of real eigenvectors for a symmetric matrix" do
-    # Fix me: should test for linearity, not for equality
-    Matrix[[1, 2],
-           [2, 1]].eigensystem.eigenvectors.should ==
-    [ Vector[0.7071067811865475, -0.7071067811865475],
-      Vector[0.7071067811865475, 0.7071067811865475]
-    ]
+    it "returns an array of real eigenvectors for a symmetric matrix" do
+      # Fix me: should test for linearity, not for equality
+      Matrix[[1, 2],
+             [2, 1]].eigensystem.eigenvectors.should ==
+      [ Vector[0.7071067811865475, -0.7071067811865475],
+        Vector[0.7071067811865475, 0.7071067811865475]
+      ]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eigenvalue_decomposition/initialize_spec.rb b/spec/ruby/library/matrix/eigenvalue_decomposition/initialize_spec.rb
index 8438f63133..02aad65c4b 100644
--- a/spec/ruby/library/matrix/eigenvalue_decomposition/initialize_spec.rb
+++ b/spec/ruby/library/matrix/eigenvalue_decomposition/initialize_spec.rb
@@ -1,24 +1,27 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::EigenvalueDecomposition#initialize" do
-  it "raises an error if argument is not a matrix" do
-    -> {
-      Matrix::EigenvalueDecomposition.new([[]])
-    }.should raise_error(TypeError)
-    -> {
-      Matrix::EigenvalueDecomposition.new(42)
-    }.should raise_error(TypeError)
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "raises an error if matrix is not square" do
-    -> {
-      Matrix::EigenvalueDecomposition.new(Matrix[[1, 2]])
-    }.should raise_error(Matrix::ErrDimensionMismatch)
-  end
+  describe "Matrix::EigenvalueDecomposition#initialize" do
+    it "raises an error if argument is not a matrix" do
+      -> {
+        Matrix::EigenvalueDecomposition.new([[]])
+      }.should raise_error(TypeError)
+      -> {
+        Matrix::EigenvalueDecomposition.new(42)
+      }.should raise_error(TypeError)
+    end
+
+    it "raises an error if matrix is not square" do
+      -> {
+        Matrix::EigenvalueDecomposition.new(Matrix[[1, 2]])
+      }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
 
-  it "never hangs" do
-    m = Matrix[ [0,0,0,0,0], [0,0,0,0,1], [0,0,0,1,0], [1,1,0,0,1], [1,0,1,0,1] ]
-    Matrix::EigenvalueDecomposition.new(m).should_not == "infinite loop"
+    it "never hangs" do
+      m = Matrix[ [0,0,0,0,0], [0,0,0,0,1], [0,0,0,1,0], [1,1,0,0,1], [1,0,1,0,1] ]
+      Matrix::EigenvalueDecomposition.new(m).should_not == "infinite loop"
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eigenvalue_decomposition/to_a_spec.rb b/spec/ruby/library/matrix/eigenvalue_decomposition/to_a_spec.rb
index 8be41a5720..352ae274b4 100644
--- a/spec/ruby/library/matrix/eigenvalue_decomposition/to_a_spec.rb
+++ b/spec/ruby/library/matrix/eigenvalue_decomposition/to_a_spec.rb
@@ -1,18 +1,21 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::EigenvalueDecomposition#to_a" do
-  before :each do
-    @a = Matrix[[14, 16], [-6, -6]]
-    @e = Matrix::EigenvalueDecomposition.new(@a)
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an array of with [V, D, V.inv]" do
-    @e.to_a.should == [@e.v, @e.d, @e.v_inv]
-  end
+  describe "Matrix::EigenvalueDecomposition#to_a" do
+    before :each do
+      @a = Matrix[[14, 16], [-6, -6]]
+      @e = Matrix::EigenvalueDecomposition.new(@a)
+    end
+
+    it "returns an array of with [V, D, V.inv]" do
+      @e.to_a.should == [@e.v, @e.d, @e.v_inv]
+    end
 
-  it "returns a factorization" do
-    v, d, v_inv = @e.to_a
-    (v * d * v_inv).map{|e| e.round(10)}.should == @a
+    it "returns a factorization" do
+      v, d, v_inv = @e.to_a
+      (v * d * v_inv).map{|e| e.round(10)}.should == @a
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/element_reference_spec.rb b/spec/ruby/library/matrix/element_reference_spec.rb
index b950d1c391..286ab851bd 100644
--- a/spec/ruby/library/matrix/element_reference_spec.rb
+++ b/spec/ruby/library/matrix/element_reference_spec.rb
@@ -1,23 +1,26 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#[]" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  before :all do
-    @m = Matrix[[0, 1, 2], [3, 4, 5], [6, 7, 8], [9, 10, 11]]
-  end
+  describe "Matrix#[]" do
+
+    before :all do
+      @m = Matrix[[0, 1, 2], [3, 4, 5], [6, 7, 8], [9, 10, 11]]
+    end
 
-  it "returns element at (i, j)" do
-    (0..3).each do |i|
-      (0..2).each do |j|
-        @m[i, j].should == (i * 3) + j
+    it "returns element at (i, j)" do
+      (0..3).each do |i|
+        (0..2).each do |j|
+          @m[i, j].should == (i * 3) + j
+        end
       end
     end
-  end
 
-  it "returns nil for an invalid index pair" do
-    @m[8,1].should be_nil
-    @m[1,8].should be_nil
-  end
+    it "returns nil for an invalid index pair" do
+      @m[8,1].should be_nil
+      @m[1,8].should be_nil
+    end
 
+  end
 end
diff --git a/spec/ruby/library/matrix/empty_spec.rb b/spec/ruby/library/matrix/empty_spec.rb
index 5f294711db..0b5d5ffe0f 100644
--- a/spec/ruby/library/matrix/empty_spec.rb
+++ b/spec/ruby/library/matrix/empty_spec.rb
@@ -1,68 +1,71 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#empty?" do
-  it "returns true when the Matrix is empty" do
-    Matrix[ ].empty?.should be_true
-    Matrix[ [], [], [] ].empty?.should be_true
-    Matrix[ [], [], [] ].transpose.empty?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns false when the Matrix has elements" do
-    Matrix[ [1, 2] ].empty?.should be_false
-    Matrix[ [1], [2] ].empty?.should be_false
-  end
+  describe "Matrix#empty?" do
+    it "returns true when the Matrix is empty" do
+      Matrix[ ].empty?.should be_true
+      Matrix[ [], [], [] ].empty?.should be_true
+      Matrix[ [], [], [] ].transpose.empty?.should be_true
+    end
+
+    it "returns false when the Matrix has elements" do
+      Matrix[ [1, 2] ].empty?.should be_false
+      Matrix[ [1], [2] ].empty?.should be_false
+    end
 
-  it "doesn't accept any parameter" do
-    ->{
-      Matrix[ [1, 2] ].empty?(42)
-    }.should raise_error(ArgumentError)
+    it "doesn't accept any parameter" do
+      ->{
+        Matrix[ [1, 2] ].empty?(42)
+      }.should raise_error(ArgumentError)
+    end
   end
-end
 
-describe "Matrix.empty" do
-  it "returns an empty matrix of the requested size" do
-    m = Matrix.empty(3, 0)
-    m.row_size.should == 3
-    m.column_size.should == 0
+  describe "Matrix.empty" do
+    it "returns an empty matrix of the requested size" do
+      m = Matrix.empty(3, 0)
+      m.row_size.should == 3
+      m.column_size.should == 0
 
-    m = Matrix.empty(0, 3)
-    m.row_size.should == 0
-    m.column_size.should == 3
-  end
+      m = Matrix.empty(0, 3)
+      m.row_size.should == 0
+      m.column_size.should == 3
+    end
 
-  it "has arguments defaulting to 0" do
-    Matrix.empty.should == Matrix.empty(0, 0)
-    Matrix.empty(42).should == Matrix.empty(42, 0)
-  end
+    it "has arguments defaulting to 0" do
+      Matrix.empty.should == Matrix.empty(0, 0)
+      Matrix.empty(42).should == Matrix.empty(42, 0)
+    end
 
-  it "does not accept more than two parameters" do
-    ->{
-      Matrix.empty(1, 2, 3)
-    }.should raise_error(ArgumentError)
-  end
+    it "does not accept more than two parameters" do
+      ->{
+        Matrix.empty(1, 2, 3)
+      }.should raise_error(ArgumentError)
+    end
 
-  it "raises an error if both dimensions are > 0" do
-    ->{
-      Matrix.empty(1, 2)
-    }.should raise_error(ArgumentError)
-  end
+    it "raises an error if both dimensions are > 0" do
+      ->{
+        Matrix.empty(1, 2)
+      }.should raise_error(ArgumentError)
+    end
 
-  it "raises an error if any dimension is < 0" do
-    ->{
-      Matrix.empty(-2, 0)
-    }.should raise_error(ArgumentError)
+    it "raises an error if any dimension is < 0" do
+      ->{
+        Matrix.empty(-2, 0)
+      }.should raise_error(ArgumentError)
 
-    ->{
-      Matrix.empty(0, -2)
-    }.should raise_error(ArgumentError)
-  end
+      ->{
+        Matrix.empty(0, -2)
+      }.should raise_error(ArgumentError)
+    end
 
-end
+  end
 
-describe "for a subclass of Matrix" do
-  it "returns an instance of that subclass" do
-    MatrixSub.empty(0, 1).should be_an_instance_of(MatrixSub)
+  describe "for a subclass of Matrix" do
+    it "returns an instance of that subclass" do
+      MatrixSub.empty(0, 1).should be_an_instance_of(MatrixSub)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/eql_spec.rb b/spec/ruby/library/matrix/eql_spec.rb
index ea26c3320d..d3f03dd6f3 100644
--- a/spec/ruby/library/matrix/eql_spec.rb
+++ b/spec/ruby/library/matrix/eql_spec.rb
@@ -1,11 +1,14 @@
 require_relative '../../spec_helper'
-require_relative 'shared/equal_value'
-require 'matrix'
 
-describe "Matrix#eql?" do
-  it_behaves_like :equal, :eql?
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/equal_value'
+  require 'matrix'
 
-  it "returns false if some elements are == but not eql?" do
-    Matrix[[1, 2],[3, 4]].eql?(Matrix[[1, 2],[3, 4.0]]).should be_false
+  describe "Matrix#eql?" do
+    it_behaves_like :equal, :eql?
+
+    it "returns false if some elements are == but not eql?" do
+      Matrix[[1, 2],[3, 4]].eql?(Matrix[[1, 2],[3, 4.0]]).should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/equal_value_spec.rb b/spec/ruby/library/matrix/equal_value_spec.rb
index 10cf1e6c29..0408a8ef3e 100644
--- a/spec/ruby/library/matrix/equal_value_spec.rb
+++ b/spec/ruby/library/matrix/equal_value_spec.rb
@@ -1,11 +1,14 @@
 require_relative '../../spec_helper'
-require_relative 'shared/equal_value'
-require 'matrix'
 
-describe "Matrix#==" do
-  it_behaves_like :equal, :==
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/equal_value'
+  require 'matrix'
 
-  it "returns true if some elements are == but not eql?" do
-    Matrix[[1, 2],[3, 4]].should == Matrix[[1, 2],[3, 4.0]]
+  describe "Matrix#==" do
+    it_behaves_like :equal, :==
+
+    it "returns true if some elements are == but not eql?" do
+      Matrix[[1, 2],[3, 4]].should == Matrix[[1, 2],[3, 4.0]]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/exponent_spec.rb b/spec/ruby/library/matrix/exponent_spec.rb
index b76e18b4cd..5262627fd5 100644
--- a/spec/ruby/library/matrix/exponent_spec.rb
+++ b/spec/ruby/library/matrix/exponent_spec.rb
@@ -1,64 +1,67 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#**" do
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  describe "given an integer _n_" do
-    it "multiples the Matrix by itself _n_ times" do
-      m = Matrix[ [7,6], [3,9] ]
-      (m ** 1).should == m
-      (m ** 2).should == Matrix[ [67, 96], [48,99] ]
-      (m ** 2).should == m * m
-      (m ** 3).should == m * m * m
-      (m ** 4).should == m * m * m * m
-      (m ** 5).should == m * m * m * m * m
-    end
-
-    it "raises a ErrDimensionMismatch for non square matrices" do
-      m = Matrix[ [1, 1], [1, 2], [2, 3]]
-      -> { m ** 3 }.should raise_error(Matrix::ErrDimensionMismatch)
-      -> { m ** 0 }.should raise_error(Matrix::ErrDimensionMismatch)
-    end
+  describe "Matrix#**" do
 
-    describe "that is < 0" do
-      it "returns the inverse of **(-n)" do
-        m = Matrix[ [1, 1], [1, 2] ]
-        (m ** -2).should == Matrix[ [5, -3], [-3, 2]]
-        (m ** -4).should == (m.inverse ** 4)
+    describe "given an integer _n_" do
+      it "multiples the Matrix by itself _n_ times" do
+        m = Matrix[ [7,6], [3,9] ]
+        (m ** 1).should == m
+        (m ** 2).should == Matrix[ [67, 96], [48,99] ]
+        (m ** 2).should == m * m
+        (m ** 3).should == m * m * m
+        (m ** 4).should == m * m * m * m
+        (m ** 5).should == m * m * m * m * m
       end
 
-      it "raises a ErrNotRegular for irregular matrices" do
-        m = Matrix[ [1, 1], [1, 1] ]
-        -> { m ** -2 }.should raise_error(Matrix::ErrNotRegular)
+      it "raises a ErrDimensionMismatch for non square matrices" do
+        m = Matrix[ [1, 1], [1, 2], [2, 3]]
+        -> { m ** 3 }.should raise_error(Matrix::ErrDimensionMismatch)
+        -> { m ** 0 }.should raise_error(Matrix::ErrDimensionMismatch)
       end
-    end
 
-    ruby_version_is '3.1.0' do # https://bugs.ruby-lang.org/issues/17521
-      describe "that is 0" do
-        it "returns the identity for square matrices" do
+      describe "that is < 0" do
+        it "returns the inverse of **(-n)" do
+          m = Matrix[ [1, 1], [1, 2] ]
+          (m ** -2).should == Matrix[ [5, -3], [-3, 2]]
+          (m ** -4).should == (m.inverse ** 4)
+        end
+
+        it "raises a ErrNotRegular for irregular matrices" do
           m = Matrix[ [1, 1], [1, 1] ]
-          (m ** 0).should == Matrix.identity(2)
+          -> { m ** -2 }.should raise_error(Matrix::ErrNotRegular)
         end
+      end
+
+      ruby_version_is '3.1.0' do # https://bugs.ruby-lang.org/issues/17521
+        describe "that is 0" do
+          it "returns the identity for square matrices" do
+            m = Matrix[ [1, 1], [1, 1] ]
+            (m ** 0).should == Matrix.identity(2)
+          end
 
-        it "raises an ErrDimensionMismatch for non-square matrices" do
-          m = Matrix[ [1, 1] ]
-          -> { m ** 0 }.should raise_error(Matrix::ErrDimensionMismatch)
+          it "raises an ErrDimensionMismatch for non-square matrices" do
+            m = Matrix[ [1, 1] ]
+            -> { m ** 0 }.should raise_error(Matrix::ErrDimensionMismatch)
+          end
         end
       end
     end
-  end
 
-  it "returns the power for non integer powers" do
-    a = Matrix[[5, 4], [4, 5]]
-    ((a ** 0.5) ** 2).round(8).should == a
-    a = Matrix[[7, 10], [15, 22]]
-    ((a ** 0.25) ** 4).round(8).should == a
-  end
+    it "returns the power for non integer powers" do
+      a = Matrix[[5, 4], [4, 5]]
+      ((a ** 0.5) ** 2).round(8).should == a
+      a = Matrix[[7, 10], [15, 22]]
+      ((a ** 0.25) ** 4).round(8).should == a
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      (MatrixSub.ins ** 1).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        (MatrixSub.ins ** 1).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/find_index_spec.rb b/spec/ruby/library/matrix/find_index_spec.rb
index c2bfa6d61a..a0e3679aef 100644
--- a/spec/ruby/library/matrix/find_index_spec.rb
+++ b/spec/ruby/library/matrix/find_index_spec.rb
@@ -1,146 +1,149 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#find_index without any argument" do
-  before :all do
-    @m = Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an Enumerator when called without a block" do
-    enum = @m.find_index
-    enum.should be_an_instance_of(Enumerator)
-    enum.to_a.should == [1, 2, 3, 4, 5, 6, 7, 8]
-  end
+  describe "Matrix#find_index without any argument" do
+    before :all do
+      @m = Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ]
+    end
 
-  it "returns nil if the block is always false" do
-    @m.find_index{false}.should be_nil
-  end
+    it "returns an Enumerator when called without a block" do
+      enum = @m.find_index
+      enum.should be_an_instance_of(Enumerator)
+      enum.to_a.should == [1, 2, 3, 4, 5, 6, 7, 8]
+    end
 
-  it "returns the first index for which the block is true" do
-    @m.find_index{|x| x >= 3}.should == [0, 2]
-  end
-end
+    it "returns nil if the block is always false" do
+      @m.find_index{false}.should be_nil
+    end
 
-describe "Matrix#find_index with a subselection argument" do
-  before :all do
-    @tests = [
-    [  Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ], {
-        diagonal: [1, 6]               ,
-        off_diagonal: [2, 3, 4, 5, 7, 8],
-        lower: [1, 5, 6]               ,
-        strict_lower: [5]              ,
-        strict_upper: [2, 3, 4, 7, 8]  ,
-        upper: [1, 2, 3, 4, 6, 7, 8]   ,
-      }
-    ],
-    [  Matrix[ [1, 2], [3, 4], [5, 6], [7, 8] ], {
-        diagonal: [1, 4]               ,
-        off_diagonal: [2, 3, 5, 6, 7, 8],
-        lower: [1, 3, 4, 5, 6, 7, 8]   ,
-        strict_lower: [3, 5, 6, 7, 8]  ,
-        strict_upper: [2]              ,
-        upper: [1, 2, 4]               ,
-      }
-    ]]
+    it "returns the first index for which the block is true" do
+      @m.find_index{|x| x >= 3}.should == [0, 2]
+    end
   end
 
-  describe "and no generic argument" do
-    it "returns an Enumerator when called without a block" do
-      @tests.each do |matrix, h|
-        h.each do |selector, result|
-          matrix.find_index(selector).should be_an_instance_of(Enumerator)
-        end
-      end
+  describe "Matrix#find_index with a subselection argument" do
+    before :all do
+      @tests = [
+      [  Matrix[ [1, 2, 3, 4], [5, 6, 7, 8] ], {
+          diagonal: [1, 6]               ,
+          off_diagonal: [2, 3, 4, 5, 7, 8],
+          lower: [1, 5, 6]               ,
+          strict_lower: [5]              ,
+          strict_upper: [2, 3, 4, 7, 8]  ,
+          upper: [1, 2, 3, 4, 6, 7, 8]   ,
+        }
+      ],
+      [  Matrix[ [1, 2], [3, 4], [5, 6], [7, 8] ], {
+          diagonal: [1, 4]               ,
+          off_diagonal: [2, 3, 5, 6, 7, 8],
+          lower: [1, 3, 4, 5, 6, 7, 8]   ,
+          strict_lower: [3, 5, 6, 7, 8]  ,
+          strict_upper: [2]              ,
+          upper: [1, 2, 4]               ,
+        }
+      ]]
     end
 
-    it "yields the rights elements" do
-      @tests.each do |matrix, h|
-        h.each do |selector, result|
-          matrix.find_index(selector).to_a.should == result
+    describe "and no generic argument" do
+      it "returns an Enumerator when called without a block" do
+        @tests.each do |matrix, h|
+          h.each do |selector, result|
+            matrix.find_index(selector).should be_an_instance_of(Enumerator)
+          end
         end
       end
-    end
 
-    it "returns the first index for which the block returns true" do
-      @tests.each do |matrix, h|
-        h.each do |selector, result|
-          cnt = result.size.div 2
-          which = result[cnt]
-          idx = matrix.find_index(selector){|x| cnt -= 1; x == which}
-          matrix[*idx].should == which
-          cnt.should == -1
+      it "yields the rights elements" do
+        @tests.each do |matrix, h|
+          h.each do |selector, result|
+            matrix.find_index(selector).to_a.should == result
+          end
         end
       end
-    end
 
-    it "returns nil if the block is always false" do
-      @tests.each do |matrix, h|
-        h.each do |selector, result|
-          matrix.find_index(selector){ nil }.should == nil
+      it "returns the first index for which the block returns true" do
+        @tests.each do |matrix, h|
+          h.each do |selector, result|
+            cnt = result.size.div 2
+            which = result[cnt]
+            idx = matrix.find_index(selector){|x| cnt -= 1; x == which}
+            matrix[*idx].should == which
+            cnt.should == -1
+          end
         end
       end
-    end
 
-  end
+      it "returns nil if the block is always false" do
+        @tests.each do |matrix, h|
+          h.each do |selector, result|
+            matrix.find_index(selector){ nil }.should == nil
+          end
+        end
+      end
 
-  describe "and a generic argument" do
-    it "ignores a block" do
-      @m.find_index(42, :diagonal){raise "oups"}.should == nil
     end
 
-    it "returns the index of the requested value" do
-      @tests.each do |matrix, h|
-        h.each do |selector, result|
-          cnt = result.size / 2
-          which = result[cnt]
-          idx = matrix.find_index(which, selector)
-          matrix[*idx].should == which
+    describe "and a generic argument" do
+      it "ignores a block" do
+        @m.find_index(42, :diagonal){raise "oups"}.should == nil
+      end
+
+      it "returns the index of the requested value" do
+        @tests.each do |matrix, h|
+          h.each do |selector, result|
+            cnt = result.size / 2
+            which = result[cnt]
+            idx = matrix.find_index(which, selector)
+            matrix[*idx].should == which
+          end
         end
       end
-    end
 
-    it "returns nil if the requested value is not found" do
-      @tests.each do |matrix, h|
-        h.each do |selector, result|
-          matrix.find_index(42, selector).should == nil
+      it "returns nil if the requested value is not found" do
+        @tests.each do |matrix, h|
+          h.each do |selector, result|
+            matrix.find_index(42, selector).should == nil
+          end
         end
       end
     end
-  end
 
-end
-
-describe "Matrix#find_index with only a generic argument" do
-  before :all do
-    @m = Matrix[ [1, 2, 3, 4], [1, 2, 3, 4] ]
   end
 
-  it "returns nil if the value is not found" do
-    @m.find_index(42).should be_nil
-  end
+  describe "Matrix#find_index with only a generic argument" do
+    before :all do
+      @m = Matrix[ [1, 2, 3, 4], [1, 2, 3, 4] ]
+    end
 
-  it "returns the first index for of the requested value" do
-    @m.find_index(3).should == [0, 2]
-  end
+    it "returns nil if the value is not found" do
+      @m.find_index(42).should be_nil
+    end
+
+    it "returns the first index for of the requested value" do
+      @m.find_index(3).should == [0, 2]
+    end
 
-  it "ignores a block" do
-    @m.find_index(4){raise "oups"}.should == [0, 3]
+    it "ignores a block" do
+      @m.find_index(4){raise "oups"}.should == [0, 3]
+    end
   end
-end
 
-describe "Matrix#find_index with two arguments" do
-  it "raises an ArgumentError for an unrecognized last argument" do
-    -> {
-      @m.find_index(1, "all"){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.find_index(1, nil){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.find_index(1, :left){}
-    }.should raise_error(ArgumentError)
-    -> {
-      @m.find_index(:diagonal, 1){}
-    }.should raise_error(ArgumentError)
+  describe "Matrix#find_index with two arguments" do
+    it "raises an ArgumentError for an unrecognized last argument" do
+      -> {
+        @m.find_index(1, "all"){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.find_index(1, nil){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.find_index(1, :left){}
+      }.should raise_error(ArgumentError)
+      -> {
+        @m.find_index(:diagonal, 1){}
+      }.should raise_error(ArgumentError)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/hash_spec.rb b/spec/ruby/library/matrix/hash_spec.rb
index 7dabcd3737..7c1970511b 100644
--- a/spec/ruby/library/matrix/hash_spec.rb
+++ b/spec/ruby/library/matrix/hash_spec.rb
@@ -1,15 +1,18 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#hash" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an Integer" do
-    Matrix[ [1,2] ].hash.should be_an_instance_of(Integer)
-  end
+  describe "Matrix#hash" do
 
-  it "returns the same value for the same matrix" do
-    data = [ [40,5], [2,7] ]
-    Matrix[ *data ].hash.should == Matrix[ *data ].hash
-  end
+    it "returns an Integer" do
+      Matrix[ [1,2] ].hash.should be_an_instance_of(Integer)
+    end
 
+    it "returns the same value for the same matrix" do
+      data = [ [40,5], [2,7] ]
+      Matrix[ *data ].hash.should == Matrix[ *data ].hash
+    end
+
+  end
 end
diff --git a/spec/ruby/library/matrix/hermitian_spec.rb b/spec/ruby/library/matrix/hermitian_spec.rb
index 177ca64d83..4038ee3fa9 100644
--- a/spec/ruby/library/matrix/hermitian_spec.rb
+++ b/spec/ruby/library/matrix/hermitian_spec.rb
@@ -1,34 +1,37 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.hermitian?" do
-  it "returns true for a hermitian Matrix" do
-    Matrix[[1, 2, Complex(0, 3)], [2, 4, 5], [Complex(0, -3), 5, 6]].hermitian?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for a 0x0 empty matrix" do
-    Matrix.empty.hermitian?.should be_true
-  end
+  describe "Matrix.hermitian?" do
+    it "returns true for a hermitian Matrix" do
+      Matrix[[1, 2, Complex(0, 3)], [2, 4, 5], [Complex(0, -3), 5, 6]].hermitian?.should be_true
+    end
 
-  it "returns false for an asymmetric Matrix" do
-    Matrix[[1, 2],[-2, 1]].hermitian?.should be_false
-  end
+    it "returns true for a 0x0 empty matrix" do
+      Matrix.empty.hermitian?.should be_true
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.hermitian?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "returns false for an asymmetric Matrix" do
+      Matrix[[1, 2],[-2, 1]].hermitian?.should be_false
+    end
+
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.hermitian?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
-  end
 
-  it "returns false for a matrix with complex values on the diagonal" do
-    Matrix[[Complex(1,1)]].hermitian?.should be_false
-    Matrix[[Complex(1,0)]].hermitian?.should be_true
+    it "returns false for a matrix with complex values on the diagonal" do
+      Matrix[[Complex(1,1)]].hermitian?.should be_false
+      Matrix[[Complex(1,0)]].hermitian?.should be_true
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/identity_spec.rb b/spec/ruby/library/matrix/identity_spec.rb
index 646462bc47..14f51c402e 100644
--- a/spec/ruby/library/matrix/identity_spec.rb
+++ b/spec/ruby/library/matrix/identity_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/identity'
 
-describe "Matrix.identity" do
-  it_behaves_like :matrix_identity, :identity
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/identity'
+
+  describe "Matrix.identity" do
+    it_behaves_like :matrix_identity, :identity
+  end
 end
diff --git a/spec/ruby/library/matrix/imag_spec.rb b/spec/ruby/library/matrix/imag_spec.rb
index 1c988753d8..a89186ec02 100644
--- a/spec/ruby/library/matrix/imag_spec.rb
+++ b/spec/ruby/library/matrix/imag_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/imaginary'
 
-describe "Matrix#imag" do
-  it_behaves_like :matrix_imaginary, :imag
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/imaginary'
+
+  describe "Matrix#imag" do
+    it_behaves_like :matrix_imaginary, :imag
+  end
 end
diff --git a/spec/ruby/library/matrix/imaginary_spec.rb b/spec/ruby/library/matrix/imaginary_spec.rb
index ceae4bbe8d..e7f0e49d31 100644
--- a/spec/ruby/library/matrix/imaginary_spec.rb
+++ b/spec/ruby/library/matrix/imaginary_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/imaginary'
 
-describe "Matrix#imaginary" do
-  it_behaves_like :matrix_imaginary, :imaginary
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/imaginary'
+
+  describe "Matrix#imaginary" do
+    it_behaves_like :matrix_imaginary, :imaginary
+  end
 end
diff --git a/spec/ruby/library/matrix/inspect_spec.rb b/spec/ruby/library/matrix/inspect_spec.rb
index 508f478252..d754c0fe7f 100644
--- a/spec/ruby/library/matrix/inspect_spec.rb
+++ b/spec/ruby/library/matrix/inspect_spec.rb
@@ -1,27 +1,30 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#inspect" do
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns a stringified representation of the Matrix" do
-    Matrix[ [1,2], [2,1] ].inspect.should == "Matrix[[1, 2], [2, 1]]"
-  end
+  describe "Matrix#inspect" do
 
-  it "returns 'Matrix.empty(...)' for empty matrices" do
-    Matrix[ [], [], [] ].inspect.should == "Matrix.empty(3, 0)"
-    Matrix.columns([ [], [], [] ]).inspect.should == "Matrix.empty(0, 3)"
-  end
+    it "returns a stringified representation of the Matrix" do
+      Matrix[ [1,2], [2,1] ].inspect.should == "Matrix[[1, 2], [2, 1]]"
+    end
 
-  it "calls inspect on its contents" do
-    obj = mock("some_value")
-    obj.should_receive(:inspect).and_return("some_value")
-    Matrix[ [1, 2], [3, obj] ].inspect.should == "Matrix[[1, 2], [3, some_value]]"
-  end
+    it "returns 'Matrix.empty(...)' for empty matrices" do
+      Matrix[ [], [], [] ].inspect.should == "Matrix.empty(3, 0)"
+      Matrix.columns([ [], [], [] ]).inspect.should == "Matrix.empty(0, 3)"
+    end
+
+    it "calls inspect on its contents" do
+      obj = mock("some_value")
+      obj.should_receive(:inspect).and_return("some_value")
+      Matrix[ [1, 2], [3, obj] ].inspect.should == "Matrix[[1, 2], [3, some_value]]"
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns a string using the subclass' name" do
-      MatrixSub.ins.inspect.should == "MatrixSub[[1, 0], [0, 1]]"
+    describe "for a subclass of Matrix" do
+      it "returns a string using the subclass' name" do
+        MatrixSub.ins.inspect.should == "MatrixSub[[1, 0], [0, 1]]"
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/inv_spec.rb b/spec/ruby/library/matrix/inv_spec.rb
index 82879a6d82..0ad817a253 100644
--- a/spec/ruby/library/matrix/inv_spec.rb
+++ b/spec/ruby/library/matrix/inv_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'shared/inverse'
 
-describe "Matrix#inv" do
-  it_behaves_like :inverse, :inv
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'shared/inverse'
+
+  describe "Matrix#inv" do
+    it_behaves_like :inverse, :inv
+  end
 end
diff --git a/spec/ruby/library/matrix/inverse_from_spec.rb b/spec/ruby/library/matrix/inverse_from_spec.rb
index 651d56a244..bca40542f6 100644
--- a/spec/ruby/library/matrix/inverse_from_spec.rb
+++ b/spec/ruby/library/matrix/inverse_from_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#inverse_from" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix#inverse_from" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/inverse_spec.rb b/spec/ruby/library/matrix/inverse_spec.rb
index fa3fa7de8a..dd9099bec5 100644
--- a/spec/ruby/library/matrix/inverse_spec.rb
+++ b/spec/ruby/library/matrix/inverse_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'shared/inverse'
 
-describe "Matrix#inverse" do
-  it_behaves_like :inverse, :inverse
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'shared/inverse'
+
+  describe "Matrix#inverse" do
+    it_behaves_like :inverse, :inverse
+  end
 end
diff --git a/spec/ruby/library/matrix/lower_triangular_spec.rb b/spec/ruby/library/matrix/lower_triangular_spec.rb
index f3aa4501f4..0223b8b619 100644
--- a/spec/ruby/library/matrix/lower_triangular_spec.rb
+++ b/spec/ruby/library/matrix/lower_triangular_spec.rb
@@ -1,24 +1,27 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.lower_triangular?" do
-  it "returns true for a square lower triangular Matrix" do
-    Matrix[[1, 0, 0], [1, 2, 0], [1, 2, 3]].lower_triangular?.should be_true
-    Matrix.diagonal([1, 2, 3]).lower_triangular?.should be_true
-    Matrix[[1, 0], [1, 2], [1, 2], [1, 2]].lower_triangular?.should be_true
-    Matrix[[1, 0, 0, 0], [1, 2, 0, 0]].lower_triangular?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for an empty Matrix" do
-    Matrix.empty(3, 0).lower_triangular?.should be_true
-    Matrix.empty(0, 3).lower_triangular?.should be_true
-    Matrix.empty(0, 0).lower_triangular?.should be_true
-  end
+  describe "Matrix.lower_triangular?" do
+    it "returns true for a square lower triangular Matrix" do
+      Matrix[[1, 0, 0], [1, 2, 0], [1, 2, 3]].lower_triangular?.should be_true
+      Matrix.diagonal([1, 2, 3]).lower_triangular?.should be_true
+      Matrix[[1, 0], [1, 2], [1, 2], [1, 2]].lower_triangular?.should be_true
+      Matrix[[1, 0, 0, 0], [1, 2, 0, 0]].lower_triangular?.should be_true
+    end
+
+    it "returns true for an empty Matrix" do
+      Matrix.empty(3, 0).lower_triangular?.should be_true
+      Matrix.empty(0, 3).lower_triangular?.should be_true
+      Matrix.empty(0, 0).lower_triangular?.should be_true
+    end
 
-  it "returns false for a non lower triangular square Matrix" do
-    Matrix[[0, 1], [0, 0]].lower_triangular?.should be_false
-    Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].lower_triangular?.should be_false
-    Matrix[[0, 1], [0, 0], [0, 0], [0, 0]].lower_triangular?.should be_false
-    Matrix[[0, 0, 0, 1], [0, 0, 0, 0]].lower_triangular?.should be_false
+    it "returns false for a non lower triangular square Matrix" do
+      Matrix[[0, 1], [0, 0]].lower_triangular?.should be_false
+      Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].lower_triangular?.should be_false
+      Matrix[[0, 1], [0, 0], [0, 0], [0, 0]].lower_triangular?.should be_false
+      Matrix[[0, 0, 0, 1], [0, 0, 0, 0]].lower_triangular?.should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/lup_decomposition/determinant_spec.rb b/spec/ruby/library/matrix/lup_decomposition/determinant_spec.rb
index 9d733066c1..1ac4bc971e 100644
--- a/spec/ruby/library/matrix/lup_decomposition/determinant_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/determinant_spec.rb
@@ -1,21 +1,24 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::LUPDecomposition#determinant" do
-  it "returns the determinant when the matrix is square" do
-    a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
-    a.lup.determinant.should == 15120 # == a.determinant
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::LUPDecomposition#determinant" do
+    it "returns the determinant when the matrix is square" do
+      a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
+      a.lup.determinant.should == 15120 # == a.determinant
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[7, 8, 9], [14, 46, 51]],
-      Matrix[[7, 8], [14, 46], [28, 82]],
-    ].each do |m|
-      lup = m.lup
-      -> {
-        lup.determinant
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[7, 8, 9], [14, 46, 51]],
+        Matrix[[7, 8], [14, 46], [28, 82]],
+      ].each do |m|
+        lup = m.lup
+        -> {
+          lup.determinant
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/lup_decomposition/initialize_spec.rb b/spec/ruby/library/matrix/lup_decomposition/initialize_spec.rb
index 36afb349e6..42f78c7540 100644
--- a/spec/ruby/library/matrix/lup_decomposition/initialize_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/initialize_spec.rb
@@ -1,13 +1,16 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::LUPDecomposition#initialize" do
-  it "raises an error if argument is not a matrix" do
-    -> {
-      Matrix::LUPDecomposition.new([[]])
-    }.should raise_error(TypeError)
-    -> {
-      Matrix::LUPDecomposition.new(42)
-    }.should raise_error(TypeError)
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::LUPDecomposition#initialize" do
+    it "raises an error if argument is not a matrix" do
+      -> {
+        Matrix::LUPDecomposition.new([[]])
+      }.should raise_error(TypeError)
+      -> {
+        Matrix::LUPDecomposition.new(42)
+      }.should raise_error(TypeError)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/lup_decomposition/l_spec.rb b/spec/ruby/library/matrix/lup_decomposition/l_spec.rb
index 9514ab5d06..6c751f12b7 100644
--- a/spec/ruby/library/matrix/lup_decomposition/l_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/l_spec.rb
@@ -1,18 +1,21 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::LUPDecomposition#l" do
-  before :each do
-    @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
-    @lu = Matrix::LUPDecomposition.new(@a)
-    @l = @lu.l
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns the first element of to_a" do
-    @l.should == @lu.to_a[0]
-  end
+  describe "Matrix::LUPDecomposition#l" do
+    before :each do
+      @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
+      @lu = Matrix::LUPDecomposition.new(@a)
+      @l = @lu.l
+    end
+
+    it "returns the first element of to_a" do
+      @l.should == @lu.to_a[0]
+    end
 
-  it "returns a lower triangular matrix" do
-    @l.lower_triangular?.should be_true
+    it "returns a lower triangular matrix" do
+      @l.lower_triangular?.should be_true
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/lup_decomposition/p_spec.rb b/spec/ruby/library/matrix/lup_decomposition/p_spec.rb
index c7b5e9196e..481f8a17d5 100644
--- a/spec/ruby/library/matrix/lup_decomposition/p_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/p_spec.rb
@@ -1,18 +1,21 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::LUPDecomposition#p" do
-  before :each do
-    @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
-    @lu = Matrix::LUPDecomposition.new(@a)
-    @p = @lu.p
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns the third element of to_a" do
-    @p.should == @lu.to_a[2]
-  end
+  describe "Matrix::LUPDecomposition#p" do
+    before :each do
+      @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
+      @lu = Matrix::LUPDecomposition.new(@a)
+      @p = @lu.p
+    end
+
+    it "returns the third element of to_a" do
+      @p.should == @lu.to_a[2]
+    end
 
-  it "returns a permutation matrix" do
-    @p.permutation?.should be_true
+    it "returns a permutation matrix" do
+      @p.permutation?.should be_true
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/lup_decomposition/solve_spec.rb b/spec/ruby/library/matrix/lup_decomposition/solve_spec.rb
index 66242627e9..773fcb3e65 100644
--- a/spec/ruby/library/matrix/lup_decomposition/solve_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/solve_spec.rb
@@ -1,52 +1,55 @@
 require_relative '../../../spec_helper'
-require 'matrix'
-
-describe "Matrix::LUPDecomposition#solve" do
-  describe "for rectangular matrices" do
-    it "raises an error for singular matrices" do
-      a = Matrix[[1, 2, 3], [1, 3, 5], [2, 5, 8]]
-      lu = Matrix::LUPDecomposition.new(a)
-      -> {
-        lu.solve(a)
-      }.should raise_error(Matrix::ErrNotRegular)
-    end
 
-    describe "for non singular matrices" do
-      before :each do
-        @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
-        @lu = Matrix::LUPDecomposition.new(@a)
-      end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-      it "returns the appropriate empty matrix when given an empty matrix" do
-        @lu.solve(Matrix.empty(3,0)).should == Matrix.empty(3,0)
-        empty = Matrix::LUPDecomposition.new(Matrix.empty(0, 0))
-        empty.solve(Matrix.empty(0,3)).should == Matrix.empty(0,3)
+  describe "Matrix::LUPDecomposition#solve" do
+    describe "for rectangular matrices" do
+      it "raises an error for singular matrices" do
+        a = Matrix[[1, 2, 3], [1, 3, 5], [2, 5, 8]]
+        lu = Matrix::LUPDecomposition.new(a)
+        -> {
+          lu.solve(a)
+        }.should raise_error(Matrix::ErrNotRegular)
       end
 
-      it "returns the right matrix when given a matrix of the appropriate size" do
-        solution = Matrix[[1, 2, 3, 4], [0, 1, 2, 3], [-1, -2, -3, -4]]
-        values = Matrix[[-2, 4, 10, 16], [-37, -28, -19, -10], [-135, -188, -241, -294]] # == @a * solution
-        @lu.solve(values).should == solution
-      end
+      describe "for non singular matrices" do
+        before :each do
+          @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
+          @lu = Matrix::LUPDecomposition.new(@a)
+        end
 
-      it "raises an error when given a matrix of the wrong size" do
-        values = Matrix[[1, 2, 3, 4], [0, 1, 2, 3]]
-        -> {
-          @lu.solve(values)
-        }.should raise_error(Matrix::ErrDimensionMismatch)
-      end
+        it "returns the appropriate empty matrix when given an empty matrix" do
+          @lu.solve(Matrix.empty(3,0)).should == Matrix.empty(3,0)
+          empty = Matrix::LUPDecomposition.new(Matrix.empty(0, 0))
+          empty.solve(Matrix.empty(0,3)).should == Matrix.empty(0,3)
+        end
 
-      it "returns the right vector when given a vector of the appropriate size" do
-        solution = Vector[1, 2, -1]
-        values = Vector[14, 55, 29] # == @a * solution
-        @lu.solve(values).should == solution
-      end
+        it "returns the right matrix when given a matrix of the appropriate size" do
+          solution = Matrix[[1, 2, 3, 4], [0, 1, 2, 3], [-1, -2, -3, -4]]
+          values = Matrix[[-2, 4, 10, 16], [-37, -28, -19, -10], [-135, -188, -241, -294]] # == @a * solution
+          @lu.solve(values).should == solution
+        end
 
-      it "raises an error when given a vector of the wrong size" do
-        values = Vector[14, 55]
-        -> {
-          @lu.solve(values)
-        }.should raise_error(Matrix::ErrDimensionMismatch)
+        it "raises an error when given a matrix of the wrong size" do
+          values = Matrix[[1, 2, 3, 4], [0, 1, 2, 3]]
+          -> {
+            @lu.solve(values)
+          }.should raise_error(Matrix::ErrDimensionMismatch)
+        end
+
+        it "returns the right vector when given a vector of the appropriate size" do
+          solution = Vector[1, 2, -1]
+          values = Vector[14, 55, 29] # == @a * solution
+          @lu.solve(values).should == solution
+        end
+
+        it "raises an error when given a vector of the wrong size" do
+          values = Vector[14, 55]
+          -> {
+            @lu.solve(values)
+          }.should raise_error(Matrix::ErrDimensionMismatch)
+        end
       end
     end
   end
diff --git a/spec/ruby/library/matrix/lup_decomposition/to_a_spec.rb b/spec/ruby/library/matrix/lup_decomposition/to_a_spec.rb
index 9b1dccbbac..8702292865 100644
--- a/spec/ruby/library/matrix/lup_decomposition/to_a_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/to_a_spec.rb
@@ -1,33 +1,36 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::LUPDecomposition#to_a" do
-  before :each do
-    @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
-    @lu = Matrix::LUPDecomposition.new(@a)
-    @to_a = @lu.to_a
-    @l, @u, @p = @to_a
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns an array of three matrices" do
-    @to_a.should be_kind_of(Array)
-    @to_a.length.should == 3
-    @to_a.each{|m| m.should be_kind_of(Matrix)}
-  end
+  describe "Matrix::LUPDecomposition#to_a" do
+    before :each do
+      @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
+      @lu = Matrix::LUPDecomposition.new(@a)
+      @to_a = @lu.to_a
+      @l, @u, @p = @to_a
+    end
 
-  it "returns [l, u, p] such that l*u == a*p" do
-    (@l * @u).should == (@p * @a)
-  end
+    it "returns an array of three matrices" do
+      @to_a.should be_kind_of(Array)
+      @to_a.length.should == 3
+      @to_a.each{|m| m.should be_kind_of(Matrix)}
+    end
 
-  it "returns the right values for rectangular matrices" do
-    [
-      Matrix[[7, 8, 9], [14, 46, 51]],
-      Matrix[[4, 11], [5, 8], [3, 4]],
-    ].each do |a|
-      l, u, p = Matrix::LUPDecomposition.new(a).to_a
-      (l * u).should == (p * a)
+    it "returns [l, u, p] such that l*u == a*p" do
+      (@l * @u).should == (@p * @a)
+    end
+
+    it "returns the right values for rectangular matrices" do
+      [
+        Matrix[[7, 8, 9], [14, 46, 51]],
+        Matrix[[4, 11], [5, 8], [3, 4]],
+      ].each do |a|
+        l, u, p = Matrix::LUPDecomposition.new(a).to_a
+        (l * u).should == (p * a)
+      end
     end
-  end
 
-  it "has other properties implied by the specs of #l, #u and #p"
+    it "has other properties implied by the specs of #l, #u and #p"
+  end
 end
diff --git a/spec/ruby/library/matrix/lup_decomposition/u_spec.rb b/spec/ruby/library/matrix/lup_decomposition/u_spec.rb
index ca3dfc1f00..cd884b88ec 100644
--- a/spec/ruby/library/matrix/lup_decomposition/u_spec.rb
+++ b/spec/ruby/library/matrix/lup_decomposition/u_spec.rb
@@ -1,18 +1,21 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::LUPDecomposition#u" do
-  before :each do
-    @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
-    @lu = Matrix::LUPDecomposition.new(@a)
-    @u = @lu.u
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns the second element of to_a" do
-    @u.should == @lu.to_a[1]
-  end
+  describe "Matrix::LUPDecomposition#u" do
+    before :each do
+      @a = Matrix[[7, 8, 9], [14, 46, 51], [28, 82, 163]]
+      @lu = Matrix::LUPDecomposition.new(@a)
+      @u = @lu.u
+    end
+
+    it "returns the second element of to_a" do
+      @u.should == @lu.to_a[1]
+    end
 
-  it "returns an upper triangular matrix" do
-    @u.upper_triangular?.should be_true
+    it "returns an upper triangular matrix" do
+      @u.upper_triangular?.should be_true
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/map_spec.rb b/spec/ruby/library/matrix/map_spec.rb
index bc07c48cda..cde0df5441 100644
--- a/spec/ruby/library/matrix/map_spec.rb
+++ b/spec/ruby/library/matrix/map_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/collect'
 
-describe "Matrix#map" do
-  it_behaves_like :collect, :map
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/collect'
+
+  describe "Matrix#map" do
+    it_behaves_like :collect, :map
+  end
 end
diff --git a/spec/ruby/library/matrix/minor_spec.rb b/spec/ruby/library/matrix/minor_spec.rb
index 009826c3d6..0a6b0823c8 100644
--- a/spec/ruby/library/matrix/minor_spec.rb
+++ b/spec/ruby/library/matrix/minor_spec.rb
@@ -1,85 +1,88 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#minor" do
-  before :each do
-    @matrix = Matrix[ [1,2], [3,4], [5,6] ]
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  describe "with start_row, nrows, start_col, ncols" do
-    it "returns the given portion of the Matrix" do
-      @matrix.minor(0,1,0,2).should == Matrix[ [1, 2] ]
-      @matrix.minor(1,2,1,1).should == Matrix[ [4], [6] ]
+  describe "Matrix#minor" do
+    before :each do
+      @matrix = Matrix[ [1,2], [3,4], [5,6] ]
     end
 
-    it "returns an empty Matrix if nrows or ncols is 0" do
-      @matrix.minor(0,0,0,0).should == Matrix[]
-      @matrix.minor(1,0,1,0).should == Matrix[]
-      @matrix.minor(1,0,1,1).should == Matrix.columns([[]])
-      @matrix.minor(1,1,1,0).should == Matrix[[]]
-    end
+    describe "with start_row, nrows, start_col, ncols" do
+      it "returns the given portion of the Matrix" do
+        @matrix.minor(0,1,0,2).should == Matrix[ [1, 2] ]
+        @matrix.minor(1,2,1,1).should == Matrix[ [4], [6] ]
+      end
 
-    it "returns nil for out-of-bounds start_row/col" do
-      r = @matrix.row_size + 1
-      c = @matrix.column_size + 1
-      @matrix.minor(r,0,0,10).should == nil
-      @matrix.minor(0,10,c,9).should == nil
-      @matrix.minor(-r,0,0,10).should == nil
-      @matrix.minor(0,10,-c,9).should == nil
-    end
+      it "returns an empty Matrix if nrows or ncols is 0" do
+        @matrix.minor(0,0,0,0).should == Matrix[]
+        @matrix.minor(1,0,1,0).should == Matrix[]
+        @matrix.minor(1,0,1,1).should == Matrix.columns([[]])
+        @matrix.minor(1,1,1,0).should == Matrix[[]]
+      end
 
-    it "returns nil for negative nrows or ncols" do
-      @matrix.minor(0,1,0,-1).should == nil
-      @matrix.minor(0,-1,0,1).should == nil
-    end
+      it "returns nil for out-of-bounds start_row/col" do
+        r = @matrix.row_size + 1
+        c = @matrix.column_size + 1
+        @matrix.minor(r,0,0,10).should == nil
+        @matrix.minor(0,10,c,9).should == nil
+        @matrix.minor(-r,0,0,10).should == nil
+        @matrix.minor(0,10,-c,9).should == nil
+      end
 
-    it "start counting backwards for start_row or start_col below zero" do
-      @matrix.minor(0, 1, -1, 1).should == @matrix.minor(0, 1, 1, 1)
-      @matrix.minor(-1, 1, 0, 1).should == @matrix.minor(2, 1, 0, 1)
-    end
+      it "returns nil for negative nrows or ncols" do
+        @matrix.minor(0,1,0,-1).should == nil
+        @matrix.minor(0,-1,0,1).should == nil
+      end
 
-    it "returns empty matrices for extreme start_row/col" do
-      @matrix.minor(3,10,1,10).should == Matrix.columns([[]])
-      @matrix.minor(1,10,2,10).should == Matrix[[], []]
-      @matrix.minor(3,0,0,10).should == Matrix.columns([[], []])
-    end
+      it "start counting backwards for start_row or start_col below zero" do
+        @matrix.minor(0, 1, -1, 1).should == @matrix.minor(0, 1, 1, 1)
+        @matrix.minor(-1, 1, 0, 1).should == @matrix.minor(2, 1, 0, 1)
+      end
 
-    it "ignores big nrows or ncols" do
-      @matrix.minor(0,1,0,20).should == Matrix[ [1, 2] ]
-      @matrix.minor(1,20,1,1).should == Matrix[ [4], [6] ]
-    end
-  end
+      it "returns empty matrices for extreme start_row/col" do
+        @matrix.minor(3,10,1,10).should == Matrix.columns([[]])
+        @matrix.minor(1,10,2,10).should == Matrix[[], []]
+        @matrix.minor(3,0,0,10).should == Matrix.columns([[], []])
+      end
 
-  describe "with col_range, row_range" do
-    it "returns the given portion of the Matrix" do
-      @matrix.minor(0..0, 0..1).should == Matrix[ [1, 2] ]
-      @matrix.minor(1..2, 1..2).should == Matrix[ [4], [6] ]
-      @matrix.minor(1...3, 1...3).should == Matrix[ [4], [6] ]
+      it "ignores big nrows or ncols" do
+        @matrix.minor(0,1,0,20).should == Matrix[ [1, 2] ]
+        @matrix.minor(1,20,1,1).should == Matrix[ [4], [6] ]
+      end
     end
 
-    it "returns nil if col_range or row_range is out of range" do
-      r = @matrix.row_size + 1
-      c = @matrix.column_size + 1
-      @matrix.minor(r..6, c..6).should == nil
-      @matrix.minor(0..1, c..6).should == nil
-      @matrix.minor(r..6, 0..1).should == nil
-      @matrix.minor(-r..6, -c..6).should == nil
-      @matrix.minor(0..1, -c..6).should == nil
-      @matrix.minor(-r..6, 0..1).should == nil
-    end
+    describe "with col_range, row_range" do
+      it "returns the given portion of the Matrix" do
+        @matrix.minor(0..0, 0..1).should == Matrix[ [1, 2] ]
+        @matrix.minor(1..2, 1..2).should == Matrix[ [4], [6] ]
+        @matrix.minor(1...3, 1...3).should == Matrix[ [4], [6] ]
+      end
 
-    it "start counting backwards for col_range or row_range below zero" do
-      @matrix.minor(0..1, -2..-1).should == @matrix.minor(0..1, 0..1)
-      @matrix.minor(0..1, -2..1).should == @matrix.minor(0..1, 0..1)
-      @matrix.minor(-2..-1, 0..1).should == @matrix.minor(1..2, 0..1)
-      @matrix.minor(-2..2, 0..1).should == @matrix.minor(1..2, 0..1)
+      it "returns nil if col_range or row_range is out of range" do
+        r = @matrix.row_size + 1
+        c = @matrix.column_size + 1
+        @matrix.minor(r..6, c..6).should == nil
+        @matrix.minor(0..1, c..6).should == nil
+        @matrix.minor(r..6, 0..1).should == nil
+        @matrix.minor(-r..6, -c..6).should == nil
+        @matrix.minor(0..1, -c..6).should == nil
+        @matrix.minor(-r..6, 0..1).should == nil
+      end
+
+      it "start counting backwards for col_range or row_range below zero" do
+        @matrix.minor(0..1, -2..-1).should == @matrix.minor(0..1, 0..1)
+        @matrix.minor(0..1, -2..1).should == @matrix.minor(0..1, 0..1)
+        @matrix.minor(-2..-1, 0..1).should == @matrix.minor(1..2, 0..1)
+        @matrix.minor(-2..2, 0..1).should == @matrix.minor(1..2, 0..1)
+      end
     end
-  end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.ins.minor(0, 1, 0, 1).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.ins.minor(0, 1, 0, 1).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/minus_spec.rb b/spec/ruby/library/matrix/minus_spec.rb
index 95cf4a6072..27dfbeaea5 100644
--- a/spec/ruby/library/matrix/minus_spec.rb
+++ b/spec/ruby/library/matrix/minus_spec.rb
@@ -1,42 +1,45 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#-" do
-  before :each do
-    @a = Matrix[ [1, 2], [3, 4] ]
-    @b = Matrix[ [4, 5], [6, 7] ]
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns the result of subtracting the corresponding elements of other from self" do
-    (@a - @b).should == Matrix[ [-3,-3], [-3,-3] ]
-  end
+  describe "Matrix#-" do
+    before :each do
+      @a = Matrix[ [1, 2], [3, 4] ]
+      @b = Matrix[ [4, 5], [6, 7] ]
+    end
 
-  it "returns an instance of Matrix" do
-    (@a - @b).should be_kind_of(Matrix)
-  end
+    it "returns the result of subtracting the corresponding elements of other from self" do
+      (@a - @b).should == Matrix[ [-3,-3], [-3,-3] ]
+    end
 
-  it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
-    -> { @a - Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
-  end
+    it "returns an instance of Matrix" do
+      (@a - @b).should be_kind_of(Matrix)
+    end
 
-  it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do
-    -> { @a - 2            }.should raise_error(Matrix::ErrOperationNotDefined)
-    -> { @a - 1.2          }.should raise_error(Matrix::ErrOperationNotDefined)
-    -> { @a - bignum_value }.should raise_error(Matrix::ErrOperationNotDefined)
-  end
+    it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
+      -> { @a - Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
 
-  it "raises a TypeError if other is of wrong type" do
-    -> { @a - nil        }.should raise_error(TypeError)
-    -> { @a - "a"        }.should raise_error(TypeError)
-    -> { @a - [ [1, 2] ] }.should raise_error(TypeError)
-    -> { @a - Object.new }.should raise_error(TypeError)
-  end
+    it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do
+      -> { @a - 2            }.should raise_error(Matrix::ErrOperationNotDefined)
+      -> { @a - 1.2          }.should raise_error(Matrix::ErrOperationNotDefined)
+      -> { @a - bignum_value }.should raise_error(Matrix::ErrOperationNotDefined)
+    end
+
+    it "raises a TypeError if other is of wrong type" do
+      -> { @a - nil        }.should raise_error(TypeError)
+      -> { @a - "a"        }.should raise_error(TypeError)
+      -> { @a - [ [1, 2] ] }.should raise_error(TypeError)
+      -> { @a - Object.new }.should raise_error(TypeError)
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      m = MatrixSub.ins
-      (m-m).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        m = MatrixSub.ins
+        (m-m).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/multiply_spec.rb b/spec/ruby/library/matrix/multiply_spec.rb
index 585f268931..841d9d95b7 100644
--- a/spec/ruby/library/matrix/multiply_spec.rb
+++ b/spec/ruby/library/matrix/multiply_spec.rb
@@ -1,68 +1,71 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#*" do
-  before :each do
-    @a = Matrix[ [1, 2], [3, 4] ]
-    @b = Matrix[ [4, 5], [6, 7] ]
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns the result of multiplying the corresponding elements of self and a Matrix" do
-    (@a * @b).should == Matrix[ [16,19], [36,43] ]
-  end
+  describe "Matrix#*" do
+    before :each do
+      @a = Matrix[ [1, 2], [3, 4] ]
+      @b = Matrix[ [4, 5], [6, 7] ]
+    end
 
-  it "returns the result of multiplying the corresponding elements of self and a Vector" do
-    (@a * Vector[1,2]).should == Vector[5, 11]
-  end
+    it "returns the result of multiplying the corresponding elements of self and a Matrix" do
+      (@a * @b).should == Matrix[ [16,19], [36,43] ]
+    end
 
-  it "returns the result of multiplying the elements of self and a Fixnum" do
-    (@a * 2).should == Matrix[ [2, 4], [6, 8] ]
-  end
+    it "returns the result of multiplying the corresponding elements of self and a Vector" do
+      (@a * Vector[1,2]).should == Vector[5, 11]
+    end
 
-  it "returns the result of multiplying the elements of self and a Bignum" do
-    (@a * bignum_value).should == Matrix[
-      [9223372036854775808, 18446744073709551616],
-      [27670116110564327424, 36893488147419103232]
-    ]
-  end
+    it "returns the result of multiplying the elements of self and a Fixnum" do
+      (@a * 2).should == Matrix[ [2, 4], [6, 8] ]
+    end
 
-  it "returns the result of multiplying the elements of self and a Float" do
-    (@a * 2.0).should == Matrix[ [2.0, 4.0], [6.0, 8.0] ]
-  end
+    it "returns the result of multiplying the elements of self and a Bignum" do
+      (@a * bignum_value).should == Matrix[
+        [9223372036854775808, 18446744073709551616],
+        [27670116110564327424, 36893488147419103232]
+      ]
+    end
 
-  it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
-    -> { @a * Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
-  end
+    it "returns the result of multiplying the elements of self and a Float" do
+      (@a * 2.0).should == Matrix[ [2.0, 4.0], [6.0, 8.0] ]
+    end
 
-  it "returns a zero matrix if (nx0) * (0xn)" do
-    (Matrix[[],[],[]] * Matrix.columns([[],[],[]])).should == Matrix.zero(3)
-  end
+    it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
+      -> { @a * Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
 
-  it "returns an empty matrix if (0xn) * (nx0)" do
-    (Matrix.columns([[],[],[]]) * Matrix[[],[],[]]).should == Matrix[]
-  end
+    it "returns a zero matrix if (nx0) * (0xn)" do
+      (Matrix[[],[],[]] * Matrix.columns([[],[],[]])).should == Matrix.zero(3)
+    end
 
-  it "returns a mx0 matrix if (mxn) * (nx0)" do
-    (Matrix[[1,2],[3,4],[5,6]] * Matrix[[],[]]).should == Matrix[[],[],[]]
-  end
+    it "returns an empty matrix if (0xn) * (nx0)" do
+      (Matrix.columns([[],[],[]]) * Matrix[[],[],[]]).should == Matrix[]
+    end
 
-  it "returns a 0xm matrix if (0xm) * (mxn)" do
-    (Matrix.columns([[], [], []]) * Matrix[[1,2],[3,4],[5,6]]).should == Matrix.columns([[],[]])
-  end
+    it "returns a mx0 matrix if (mxn) * (nx0)" do
+      (Matrix[[1,2],[3,4],[5,6]] * Matrix[[],[]]).should == Matrix[[],[],[]]
+    end
 
-  it "raises a TypeError if other is of wrong type" do
-    -> { @a * nil        }.should raise_error(TypeError)
-    -> { @a * "a"        }.should raise_error(TypeError)
-    -> { @a * [ [1, 2] ] }.should raise_error(TypeError)
-    -> { @a * Object.new }.should raise_error(TypeError)
-  end
+    it "returns a 0xm matrix if (0xm) * (mxn)" do
+      (Matrix.columns([[], [], []]) * Matrix[[1,2],[3,4],[5,6]]).should == Matrix.columns([[],[]])
+    end
+
+    it "raises a TypeError if other is of wrong type" do
+      -> { @a * nil        }.should raise_error(TypeError)
+      -> { @a * "a"        }.should raise_error(TypeError)
+      -> { @a * [ [1, 2] ] }.should raise_error(TypeError)
+      -> { @a * Object.new }.should raise_error(TypeError)
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      m = MatrixSub.ins
-      (m*m).should be_an_instance_of(MatrixSub)
-      (m*1).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        m = MatrixSub.ins
+        (m*m).should be_an_instance_of(MatrixSub)
+        (m*1).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/new_spec.rb b/spec/ruby/library/matrix/new_spec.rb
index 3005066846..4be2e17116 100644
--- a/spec/ruby/library/matrix/new_spec.rb
+++ b/spec/ruby/library/matrix/new_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.new" do
-  it "is private" do
-    Matrix.should have_private_method(:new)
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix.new" do
+    it "is private" do
+      Matrix.should have_private_method(:new)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/normal_spec.rb b/spec/ruby/library/matrix/normal_spec.rb
index a9e6c645fa..2f2e138c1b 100644
--- a/spec/ruby/library/matrix/normal_spec.rb
+++ b/spec/ruby/library/matrix/normal_spec.rb
@@ -1,26 +1,29 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.normal?" do
-  # it "returns false for non normal matrices" do
-  #   Matrix[[0, 1], [1, 2]].should_not.normal?
-  # end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for normal matrices" do
-    Matrix[[1, 1, 0], [0, 1, 1], [1, 0, 1]].should.normal?
-    Matrix[[0, Complex(0, 2)], [Complex(0, -2), 0]].should.normal?
-  end
+  describe "Matrix.normal?" do
+    # it "returns false for non normal matrices" do
+    #   Matrix[[0, 1], [1, 2]].should_not.normal?
+    # end
+
+    it "returns true for normal matrices" do
+      Matrix[[1, 1, 0], [0, 1, 1], [1, 0, 1]].should.normal?
+      Matrix[[0, Complex(0, 2)], [Complex(0, -2), 0]].should.normal?
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.normal?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.normal?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/orthogonal_spec.rb b/spec/ruby/library/matrix/orthogonal_spec.rb
index 26afe89ff0..eb06305040 100644
--- a/spec/ruby/library/matrix/orthogonal_spec.rb
+++ b/spec/ruby/library/matrix/orthogonal_spec.rb
@@ -1,26 +1,29 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.orthogonal?" do
-  it "returns false for non orthogonal matrices" do
-    Matrix[[0, 1], [1, 2]].should_not.orthogonal?
-    Matrix[[1, 1, 0], [0, 1, 1], [1, 0, 1]].should_not.orthogonal?
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for orthogonal matrices" do
-    Matrix[[0, 1], [1, 0]].should.orthogonal?
-  end
+  describe "Matrix.orthogonal?" do
+    it "returns false for non orthogonal matrices" do
+      Matrix[[0, 1], [1, 2]].should_not.orthogonal?
+      Matrix[[1, 1, 0], [0, 1, 1], [1, 0, 1]].should_not.orthogonal?
+    end
+
+    it "returns true for orthogonal matrices" do
+      Matrix[[0, 1], [1, 0]].should.orthogonal?
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.orthogonal?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.orthogonal?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/permutation_spec.rb b/spec/ruby/library/matrix/permutation_spec.rb
index 825a9d982c..ed8edad755 100644
--- a/spec/ruby/library/matrix/permutation_spec.rb
+++ b/spec/ruby/library/matrix/permutation_spec.rb
@@ -1,32 +1,35 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#permutation?" do
-  it "returns true for a permutation Matrix" do
-    Matrix[[0, 1, 0], [0, 0, 1], [1, 0, 0]].permutation?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns false for a non permutation square Matrix" do
-    Matrix[[0, 1], [0, 0]].permutation?.should be_false
-    Matrix[[-1, 0], [0, -1]].permutation?.should be_false
-    Matrix[[1, 0], [1, 0]].permutation?.should be_false
-    Matrix[[1, 0], [1, 1]].permutation?.should be_false
-  end
+  describe "Matrix#permutation?" do
+    it "returns true for a permutation Matrix" do
+      Matrix[[0, 1, 0], [0, 0, 1], [1, 0, 0]].permutation?.should be_true
+    end
 
-  it "returns true for an empty 0x0 matrix" do
-    Matrix.empty(0,0).permutation?.should be_true
-  end
+    it "returns false for a non permutation square Matrix" do
+      Matrix[[0, 1], [0, 0]].permutation?.should be_false
+      Matrix[[-1, 0], [0, -1]].permutation?.should be_false
+      Matrix[[1, 0], [1, 0]].permutation?.should be_false
+      Matrix[[1, 0], [1, 1]].permutation?.should be_false
+    end
+
+    it "returns true for an empty 0x0 matrix" do
+      Matrix.empty(0,0).permutation?.should be_true
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.permutation?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.permutation?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/plus_spec.rb b/spec/ruby/library/matrix/plus_spec.rb
index 2706bad060..99e6615778 100644
--- a/spec/ruby/library/matrix/plus_spec.rb
+++ b/spec/ruby/library/matrix/plus_spec.rb
@@ -1,42 +1,45 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#+" do
-  before :each do
-    @a = Matrix[ [1,2], [3,4] ]
-    @b = Matrix[ [4,5], [6,7] ]
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns the result of adding the corresponding elements of self and other" do
-    (@a + @b).should == Matrix[ [5,7], [9,11] ]
-  end
+  describe "Matrix#+" do
+    before :each do
+      @a = Matrix[ [1,2], [3,4] ]
+      @b = Matrix[ [4,5], [6,7] ]
+    end
 
-  it "returns an instance of Matrix" do
-    (@a + @b).should be_kind_of(Matrix)
-  end
+    it "returns the result of adding the corresponding elements of self and other" do
+      (@a + @b).should == Matrix[ [5,7], [9,11] ]
+    end
 
-  it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
-    -> { @a + Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
-  end
+    it "returns an instance of Matrix" do
+      (@a + @b).should be_kind_of(Matrix)
+    end
 
-  it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do
-    -> { @a + 2            }.should raise_error(ExceptionForMatrix::ErrOperationNotDefined)
-    -> { @a + 1.2          }.should raise_error(ExceptionForMatrix::ErrOperationNotDefined)
-    -> { @a + bignum_value }.should raise_error(ExceptionForMatrix::ErrOperationNotDefined)
-  end
+    it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
+      -> { @a + Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
 
-  it "raises a TypeError if other is of wrong type" do
-    -> { @a + nil        }.should raise_error(TypeError)
-    -> { @a + "a"        }.should raise_error(TypeError)
-    -> { @a + [ [1, 2] ] }.should raise_error(TypeError)
-    -> { @a + Object.new }.should raise_error(TypeError)
-  end
+    it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do
+      -> { @a + 2            }.should raise_error(ExceptionForMatrix::ErrOperationNotDefined)
+      -> { @a + 1.2          }.should raise_error(ExceptionForMatrix::ErrOperationNotDefined)
+      -> { @a + bignum_value }.should raise_error(ExceptionForMatrix::ErrOperationNotDefined)
+    end
+
+    it "raises a TypeError if other is of wrong type" do
+      -> { @a + nil        }.should raise_error(TypeError)
+      -> { @a + "a"        }.should raise_error(TypeError)
+      -> { @a + [ [1, 2] ] }.should raise_error(TypeError)
+      -> { @a + Object.new }.should raise_error(TypeError)
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      m = MatrixSub.ins
-      (m+m).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        m = MatrixSub.ins
+        (m+m).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/rank_spec.rb b/spec/ruby/library/matrix/rank_spec.rb
index d4403d23ed..fc795b58c1 100644
--- a/spec/ruby/library/matrix/rank_spec.rb
+++ b/spec/ruby/library/matrix/rank_spec.rb
@@ -1,19 +1,22 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#rank" do
-  it "returns the rank of the Matrix" do
-    Matrix[ [7,6], [3,9] ].rank.should == 2
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "doesn't loop forever" do
-    Matrix[ [1,2,3], [4,5,6], [7,8,9] ].rank.should == 2
-    Matrix[ [1, 2, 0, 3], [1, -2, 3, 0], [0, 0, 4, 8], [2, 4, 0, 6] ].rank.
-    should == 3
-  end
+  describe "Matrix#rank" do
+    it "returns the rank of the Matrix" do
+      Matrix[ [7,6], [3,9] ].rank.should == 2
+    end
+
+    it "doesn't loop forever" do
+      Matrix[ [1,2,3], [4,5,6], [7,8,9] ].rank.should == 2
+      Matrix[ [1, 2, 0, 3], [1, -2, 3, 0], [0, 0, 4, 8], [2, 4, 0, 6] ].rank.
+      should == 3
+    end
 
-  it "works for some easy rectangular matrices" do
-    Matrix[[0,0],[0,0],[1,0]].rank.should == 1
-    Matrix[[0,1],[0,0],[1,0]].rank.should == 2
+    it "works for some easy rectangular matrices" do
+      Matrix[[0,0],[0,0],[1,0]].rank.should == 1
+      Matrix[[0,1],[0,0],[1,0]].rank.should == 2
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/real_spec.rb b/spec/ruby/library/matrix/real_spec.rb
index 38033c63c8..63a6bde923 100644
--- a/spec/ruby/library/matrix/real_spec.rb
+++ b/spec/ruby/library/matrix/real_spec.rb
@@ -1,43 +1,46 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#real?" do
-  it "returns true for matrices with all real entries" do
-    Matrix[ [1,   2], [3, 4] ].real?.should be_true
-    Matrix[ [1.9, 2], [3, 4] ].real?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns true for empty matrices" do
-    Matrix.empty.real?.should be_true
-  end
+  describe "Matrix#real?" do
+    it "returns true for matrices with all real entries" do
+      Matrix[ [1,   2], [3, 4] ].real?.should be_true
+      Matrix[ [1.9, 2], [3, 4] ].real?.should be_true
+    end
 
-  it "returns false if one element is a Complex" do
-    Matrix[ [Complex(1,1), 2], [3, 4] ].real?.should be_false
-  end
+    it "returns true for empty matrices" do
+      Matrix.empty.real?.should be_true
+    end
 
-  # Guard against the Mathn library
-  guard -> { !defined?(Math.rsqrt) } do
-    it "returns false if one element is a Complex whose imaginary part is 0" do
-      Matrix[ [Complex(1,0), 2], [3, 4] ].real?.should be_false
+    it "returns false if one element is a Complex" do
+      Matrix[ [Complex(1,1), 2], [3, 4] ].real?.should be_false
     end
-  end
-end
 
-describe "Matrix#real" do
-  it "returns a matrix with the real part of the elements of the receiver" do
-    Matrix[ [1,   2], [3, 4] ].real.should == Matrix[ [1,   2], [3, 4] ]
-    Matrix[ [1.9, Complex(1,1)], [Complex(-0.42, 0), 4] ].real.should == Matrix[ [1.9, 1], [-0.42, 4] ]
+    # Guard against the Mathn library
+    guard -> { !defined?(Math.rsqrt) } do
+      it "returns false if one element is a Complex whose imaginary part is 0" do
+        Matrix[ [Complex(1,0), 2], [3, 4] ].real?.should be_false
+      end
+    end
   end
 
-  it "returns empty matrices on the same size if empty" do
-    Matrix.empty(0, 3).real.should == Matrix.empty(0, 3)
-    Matrix.empty(3, 0).real.should == Matrix.empty(3, 0)
-  end
+  describe "Matrix#real" do
+    it "returns a matrix with the real part of the elements of the receiver" do
+      Matrix[ [1,   2], [3, 4] ].real.should == Matrix[ [1,   2], [3, 4] ]
+      Matrix[ [1.9, Complex(1,1)], [Complex(-0.42, 0), 4] ].real.should == Matrix[ [1.9, 1], [-0.42, 4] ]
+    end
+
+    it "returns empty matrices on the same size if empty" do
+      Matrix.empty(0, 3).real.should == Matrix.empty(0, 3)
+      Matrix.empty(3, 0).real.should == Matrix.empty(3, 0)
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.ins.real.should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.ins.real.should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/rect_spec.rb b/spec/ruby/library/matrix/rect_spec.rb
index 83a0404e47..b3b7ac05c9 100644
--- a/spec/ruby/library/matrix/rect_spec.rb
+++ b/spec/ruby/library/matrix/rect_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/rectangular'
 
-describe "Matrix#rect" do
-  it_behaves_like :matrix_rectangular, :rect
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/rectangular'
+
+  describe "Matrix#rect" do
+    it_behaves_like :matrix_rectangular, :rect
+  end
 end
diff --git a/spec/ruby/library/matrix/rectangular_spec.rb b/spec/ruby/library/matrix/rectangular_spec.rb
index a235fac640..1fc2e0e60d 100644
--- a/spec/ruby/library/matrix/rectangular_spec.rb
+++ b/spec/ruby/library/matrix/rectangular_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/rectangular'
 
-describe "Matrix#rectangular" do
-  it_behaves_like :matrix_rectangular, :rectangular
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/rectangular'
+
+  describe "Matrix#rectangular" do
+    it_behaves_like :matrix_rectangular, :rectangular
+  end
 end
diff --git a/spec/ruby/library/matrix/regular_spec.rb b/spec/ruby/library/matrix/regular_spec.rb
index 3699d0ef8b..f6688bba30 100644
--- a/spec/ruby/library/matrix/regular_spec.rb
+++ b/spec/ruby/library/matrix/regular_spec.rb
@@ -1,31 +1,34 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#regular?" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns false for singular matrices" do
-    m = Matrix[ [1,2,3], [3,4,3], [0,0,0] ]
-    m.regular?.should be_false
+  describe "Matrix#regular?" do
 
-    m = Matrix[ [1,2,9], [3,4,9], [1,2,9] ]
-    m.regular?.should be_false
-  end
+    it "returns false for singular matrices" do
+      m = Matrix[ [1,2,3], [3,4,3], [0,0,0] ]
+      m.regular?.should be_false
 
-  it "returns true if the Matrix is regular" do
-    Matrix[ [0,1], [1,0] ].regular?.should be_true
-  end
+      m = Matrix[ [1,2,9], [3,4,9], [1,2,9] ]
+      m.regular?.should be_false
+    end
 
-  it "returns true for an empty 0x0 matrix" do
-    Matrix.empty(0,0).regular?.should be_true
-  end
+    it "returns true if the Matrix is regular" do
+      Matrix[ [0,1], [1,0] ].regular?.should be_true
+    end
+
+    it "returns true for an empty 0x0 matrix" do
+      Matrix.empty(0,0).regular?.should be_true
+    end
 
-  it "raises an error for rectangular matrices" do
-    -> {
-      Matrix[[1], [2], [3]].regular?
-    }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      -> {
+        Matrix[[1], [2], [3]].regular?
+      }.should raise_error(Matrix::ErrDimensionMismatch)
 
-    -> {
-      Matrix.empty(3,0).regular?
-    }.should raise_error(Matrix::ErrDimensionMismatch)
+      -> {
+        Matrix.empty(3,0).regular?
+      }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/round_spec.rb b/spec/ruby/library/matrix/round_spec.rb
index 1dc29df890..db33268414 100644
--- a/spec/ruby/library/matrix/round_spec.rb
+++ b/spec/ruby/library/matrix/round_spec.rb
@@ -1,21 +1,24 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix#round" do
-  it "returns a matrix with all entries rounded" do
-    Matrix[ [1,   2.34], [5.67, 8] ].round.should == Matrix[ [1, 2], [6, 8] ]
-    Matrix[ [1,   2.34], [5.67, 8] ].round(1).should == Matrix[ [1, 2.3], [5.7, 8] ]
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns empty matrices on the same size if empty" do
-    Matrix.empty(0, 3).round.should == Matrix.empty(0, 3)
-    Matrix.empty(3, 0).round(42).should == Matrix.empty(3, 0)
-  end
+  describe "Matrix#round" do
+    it "returns a matrix with all entries rounded" do
+      Matrix[ [1,   2.34], [5.67, 8] ].round.should == Matrix[ [1, 2], [6, 8] ]
+      Matrix[ [1,   2.34], [5.67, 8] ].round(1).should == Matrix[ [1, 2.3], [5.7, 8] ]
+    end
+
+    it "returns empty matrices on the same size if empty" do
+      Matrix.empty(0, 3).round.should == Matrix.empty(0, 3)
+      Matrix.empty(3, 0).round(42).should == Matrix.empty(3, 0)
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.ins.round.should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.ins.round.should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/row_size_spec.rb b/spec/ruby/library/matrix/row_size_spec.rb
index eb3aef2e2f..fca5a846ab 100644
--- a/spec/ruby/library/matrix/row_size_spec.rb
+++ b/spec/ruby/library/matrix/row_size_spec.rb
@@ -1,13 +1,16 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#row_size" do
-  it "returns the number rows" do
-    Matrix[ [1,2], [3, 4], [5, 6] ].row_size.should == 3
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns the number rows even for some empty matrices" do
-    Matrix[ [], [], [] ].row_size.should == 3
-  end
+  describe "Matrix#row_size" do
+    it "returns the number rows" do
+      Matrix[ [1,2], [3, 4], [5, 6] ].row_size.should == 3
+    end
 
+    it "returns the number rows even for some empty matrices" do
+      Matrix[ [], [], [] ].row_size.should == 3
+    end
+
+  end
 end
diff --git a/spec/ruby/library/matrix/row_spec.rb b/spec/ruby/library/matrix/row_spec.rb
index 00b1f02a8e..eb05cd9273 100644
--- a/spec/ruby/library/matrix/row_spec.rb
+++ b/spec/ruby/library/matrix/row_spec.rb
@@ -1,36 +1,39 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#row" do
-  before :all do
-    @m = Matrix[ [1, 2], [2, 3], [3, 4] ]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns a Vector when called without a block" do
-    @m.row(0).should == Vector[1,2]
-  end
+  describe "Matrix#row" do
+    before :all do
+      @m = Matrix[ [1, 2], [2, 3], [3, 4] ]
+    end
 
-  it "yields the elements of the row when called with a block" do
-    a = []
-    @m.row(0) {|x| a << x}
-    a.should == [1,2]
-  end
+    it "returns a Vector when called without a block" do
+      @m.row(0).should == Vector[1,2]
+    end
 
-  it "counts backwards for negative argument" do
-    @m.row(-1).should == Vector[3, 4]
-  end
+    it "yields the elements of the row when called with a block" do
+      a = []
+      @m.row(0) {|x| a << x}
+      a.should == [1,2]
+    end
 
-  it "returns self when called with a block" do
-    @m.row(0) { |x| x }.should equal(@m)
-  end
+    it "counts backwards for negative argument" do
+      @m.row(-1).should == Vector[3, 4]
+    end
 
-  it "returns nil when out of bounds" do
-    @m.row(3).should == nil
-    @m.row(-4).should == nil
-  end
+    it "returns self when called with a block" do
+      @m.row(0) { |x| x }.should equal(@m)
+    end
+
+    it "returns nil when out of bounds" do
+      @m.row(3).should == nil
+      @m.row(-4).should == nil
+    end
 
-  it "never yields when out of bounds" do
-    -> { @m.row(3){ raise } }.should_not raise_error
-    -> { @m.row(-4){ raise } }.should_not raise_error
+    it "never yields when out of bounds" do
+      -> { @m.row(3){ raise } }.should_not raise_error
+      -> { @m.row(-4){ raise } }.should_not raise_error
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/row_vector_spec.rb b/spec/ruby/library/matrix/row_vector_spec.rb
index 341437ee05..4c97d6013a 100644
--- a/spec/ruby/library/matrix/row_vector_spec.rb
+++ b/spec/ruby/library/matrix/row_vector_spec.rb
@@ -1,24 +1,27 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.row_vector" do
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns a Matrix" do
-    Matrix.row_vector([]).should be_an_instance_of(Matrix)
-  end
+  describe "Matrix.row_vector" do
 
-  it "returns a single-row Matrix with the specified values" do
-    Matrix.row_vector([1,2]).should == Matrix[ [1,2] ]
-  end
+    it "returns a Matrix" do
+      Matrix.row_vector([]).should be_an_instance_of(Matrix)
+    end
 
-  it "returns a 1x0 matrix when called with an empty Array" do
-    Matrix.row_vector([]).should == Matrix[ [] ]
-  end
+    it "returns a single-row Matrix with the specified values" do
+      Matrix.row_vector([1,2]).should == Matrix[ [1,2] ]
+    end
+
+    it "returns a 1x0 matrix when called with an empty Array" do
+      Matrix.row_vector([]).should == Matrix[ [] ]
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.row_vector([1]).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.row_vector([1]).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/row_vectors_spec.rb b/spec/ruby/library/matrix/row_vectors_spec.rb
index 6f99c439a6..d01a4ca10d 100644
--- a/spec/ruby/library/matrix/row_vectors_spec.rb
+++ b/spec/ruby/library/matrix/row_vectors_spec.rb
@@ -1,26 +1,29 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#row_vectors" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  before :each do
-    @vectors = Matrix[ [1,2], [3,4] ].row_vectors
-  end
+  describe "Matrix#row_vectors" do
 
-  it "returns an Array" do
-    Matrix[ [1,2], [3,4] ].row_vectors.should be_an_instance_of(Array)
-  end
+    before :each do
+      @vectors = Matrix[ [1,2], [3,4] ].row_vectors
+    end
 
-  it "returns an Array of Vectors" do
-    @vectors.all? {|v| v.should be_an_instance_of(Vector)}
-  end
+    it "returns an Array" do
+      Matrix[ [1,2], [3,4] ].row_vectors.should be_an_instance_of(Array)
+    end
 
-  it "returns each row as a Vector" do
-    @vectors.should == [Vector[1,2], Vector[3,4]]
-  end
+    it "returns an Array of Vectors" do
+      @vectors.all? {|v| v.should be_an_instance_of(Vector)}
+    end
+
+    it "returns each row as a Vector" do
+      @vectors.should == [Vector[1,2], Vector[3,4]]
+    end
 
-  it "returns an empty Array for empty matrices" do
-    Matrix[].row_vectors.should == []
-    Matrix[ [] ].row_vectors.should == [ Vector[] ]
+    it "returns an empty Array for empty matrices" do
+      Matrix[].row_vectors.should == []
+      Matrix[ [] ].row_vectors.should == [ Vector[] ]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/rows_spec.rb b/spec/ruby/library/matrix/rows_spec.rb
index 41ba635775..5f0515a37b 100644
--- a/spec/ruby/library/matrix/rows_spec.rb
+++ b/spec/ruby/library/matrix/rows_spec.rb
@@ -1,41 +1,44 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.rows" do
-  before :each do
-    @a = [1, 2]
-    @b = [3, 4]
-    @m = Matrix.rows([@a, @b])
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "returns a Matrix" do
-    @m.should be_kind_of(Matrix)
-  end
+  describe "Matrix.rows" do
+    before :each do
+      @a = [1, 2]
+      @b = [3, 4]
+      @m = Matrix.rows([@a, @b])
+    end
 
-  it "creates a matrix from argument rows" do
-    @m.row(0).to_a.should == @a
-    @m.row(1).to_a.should == @b
-  end
+    it "returns a Matrix" do
+      @m.should be_kind_of(Matrix)
+    end
 
-  it "copies the original rows by default" do
-    @a << 3
-    @b << 6
-    @m.row(0).should_not equal(@a)
-    @m.row(1).should_not equal(@b)
-  end
+    it "creates a matrix from argument rows" do
+      @m.row(0).to_a.should == @a
+      @m.row(1).to_a.should == @b
+    end
 
-  it "references the original rows if copy is false" do
-    @m_ref = Matrix.rows([@a, @b], false)
-    @a << 3
-    @b << 6
-    @m_ref.row(0).to_a.should == @a
-    @m_ref.row(1).to_a.should == @b
-  end
+    it "copies the original rows by default" do
+      @a << 3
+      @b << 6
+      @m.row(0).should_not equal(@a)
+      @m.row(1).should_not equal(@b)
+    end
+
+    it "references the original rows if copy is false" do
+      @m_ref = Matrix.rows([@a, @b], false)
+      @a << 3
+      @b << 6
+      @m_ref.row(0).to_a.should == @a
+      @m_ref.row(1).to_a.should == @b
+    end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.rows([[0, 1], [0, 1]]).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.rows([[0, 1], [0, 1]]).should be_an_instance_of(MatrixSub)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/scalar/Fail_spec.rb b/spec/ruby/library/matrix/scalar/Fail_spec.rb
index 9d8f9bd5e8..4f774eda28 100644
--- a/spec/ruby/library/matrix/scalar/Fail_spec.rb
+++ b/spec/ruby/library/matrix/scalar/Fail_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#Fail" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#Fail" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/Raise_spec.rb b/spec/ruby/library/matrix/scalar/Raise_spec.rb
index 27e11c1f77..b405b6d6c5 100644
--- a/spec/ruby/library/matrix/scalar/Raise_spec.rb
+++ b/spec/ruby/library/matrix/scalar/Raise_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#Raise" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#Raise" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/divide_spec.rb b/spec/ruby/library/matrix/scalar/divide_spec.rb
index 5d726943fe..0ef2206bf6 100644
--- a/spec/ruby/library/matrix/scalar/divide_spec.rb
+++ b/spec/ruby/library/matrix/scalar/divide_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#/" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#/" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/exponent_spec.rb b/spec/ruby/library/matrix/scalar/exponent_spec.rb
index 8e9ef52ff2..87eea283d1 100644
--- a/spec/ruby/library/matrix/scalar/exponent_spec.rb
+++ b/spec/ruby/library/matrix/scalar/exponent_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#**" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#**" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/included_spec.rb b/spec/ruby/library/matrix/scalar/included_spec.rb
index cb3beb2ecd..bab80e5120 100644
--- a/spec/ruby/library/matrix/scalar/included_spec.rb
+++ b/spec/ruby/library/matrix/scalar/included_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar.included" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar.included" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/initialize_spec.rb b/spec/ruby/library/matrix/scalar/initialize_spec.rb
index 23145ad0de..af51562b43 100644
--- a/spec/ruby/library/matrix/scalar/initialize_spec.rb
+++ b/spec/ruby/library/matrix/scalar/initialize_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#initialize" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#initialize" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/minus_spec.rb b/spec/ruby/library/matrix/scalar/minus_spec.rb
index c727ea1659..966db1d75b 100644
--- a/spec/ruby/library/matrix/scalar/minus_spec.rb
+++ b/spec/ruby/library/matrix/scalar/minus_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#-" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#-" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/multiply_spec.rb b/spec/ruby/library/matrix/scalar/multiply_spec.rb
index 1a2a83d83e..21caac478b 100644
--- a/spec/ruby/library/matrix/scalar/multiply_spec.rb
+++ b/spec/ruby/library/matrix/scalar/multiply_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#*" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#*" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar/plus_spec.rb b/spec/ruby/library/matrix/scalar/plus_spec.rb
index c94689a702..78cdf9367f 100644
--- a/spec/ruby/library/matrix/scalar/plus_spec.rb
+++ b/spec/ruby/library/matrix/scalar/plus_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Matrix::Scalar#+" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix::Scalar#+" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/scalar_spec.rb b/spec/ruby/library/matrix/scalar_spec.rb
index 7fdd64c9d9..1ec64d2d78 100644
--- a/spec/ruby/library/matrix/scalar_spec.rb
+++ b/spec/ruby/library/matrix/scalar_spec.rb
@@ -1,65 +1,68 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.scalar" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  before :each do
-    @side = 3
-    @value = 8
-    @a = Matrix.scalar(@side, @value)
-  end
+  describe "Matrix.scalar" do
 
-  it "returns a Matrix" do
-    @a.should be_kind_of(Matrix)
-  end
+    before :each do
+      @side = 3
+      @value = 8
+      @a = Matrix.scalar(@side, @value)
+    end
 
-  it "returns a n x n matrix" do
-    @a.row_size.should == @side
-    @a.column_size.should == @side
-  end
+    it "returns a Matrix" do
+      @a.should be_kind_of(Matrix)
+    end
 
-  it "initializes diagonal to value" do
-    ([email protected]_size).each do |i|
-      @a[i, i].should == @value
+    it "returns a n x n matrix" do
+      @a.row_size.should == @side
+      @a.column_size.should == @side
+    end
+
+    it "initializes diagonal to value" do
+      ([email protected]_size).each do |i|
+        @a[i, i].should == @value
+      end
     end
-  end
 
-  it "initializes all non-diagonal values to 0" do
-    ([email protected]_size).each do |i|
-      ([email protected]_size).each do |j|
-        if i != j
-          @a[i, j].should == 0
+    it "initializes all non-diagonal values to 0" do
+      ([email protected]_size).each do |i|
+        ([email protected]_size).each do |j|
+          if i != j
+            @a[i, j].should == 0
+          end
         end
       end
     end
-  end
 
-  before :each do
-    @side = 3
-    @value = 8
-    @a = Matrix.scalar(@side, @value)
-  end
+    before :each do
+      @side = 3
+      @value = 8
+      @a = Matrix.scalar(@side, @value)
+    end
 
-  it "returns a Matrix" do
-    @a.should be_kind_of(Matrix)
-  end
+    it "returns a Matrix" do
+      @a.should be_kind_of(Matrix)
+    end
 
-  it "returns a square matrix, where the first argument specifies the side of the square" do
-    @a.row_size.should == @side
-    @a.column_size.should == @side
-  end
+    it "returns a square matrix, where the first argument specifies the side of the square" do
+      @a.row_size.should == @side
+      @a.column_size.should == @side
+    end
 
-  it "puts the second argument in all diagonal values" do
-    ([email protected]_size).each do |i|
-      @a[i, i].should == @value
+    it "puts the second argument in all diagonal values" do
+      ([email protected]_size).each do |i|
+        @a[i, i].should == @value
+      end
     end
-  end
 
-  it "fills all values not on the main diagonal with 0" do
-    ([email protected]_size).each do |i|
-      ([email protected]_size).each do |j|
-        if i != j
-          @a[i, j].should == 0
+    it "fills all values not on the main diagonal with 0" do
+      ([email protected]_size).each do |i|
+        ([email protected]_size).each do |j|
+          if i != j
+            @a[i, j].should == 0
+          end
         end
       end
     end
diff --git a/spec/ruby/library/matrix/singular_spec.rb b/spec/ruby/library/matrix/singular_spec.rb
index 7bba36a54a..341c2675a8 100644
--- a/spec/ruby/library/matrix/singular_spec.rb
+++ b/spec/ruby/library/matrix/singular_spec.rb
@@ -1,31 +1,34 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#singular?" do
-  it "returns true for singular matrices" do
-    m = Matrix[ [1,2,3], [3,4,3], [0,0,0] ]
-    m.singular?.should be_true
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-    m = Matrix[ [1,2,9], [3,4,9], [1,2,9] ]
-    m.singular?.should be_true
-  end
+  describe "Matrix#singular?" do
+    it "returns true for singular matrices" do
+      m = Matrix[ [1,2,3], [3,4,3], [0,0,0] ]
+      m.singular?.should be_true
 
-  it "returns false if the Matrix is regular" do
-    Matrix[ [0,1], [1,0] ].singular?.should be_false
-  end
+      m = Matrix[ [1,2,9], [3,4,9], [1,2,9] ]
+      m.singular?.should be_true
+    end
 
-  it "returns false for an empty 0x0 matrix" do
-    Matrix.empty(0,0).singular?.should be_false
-  end
+    it "returns false if the Matrix is regular" do
+      Matrix[ [0,1], [1,0] ].singular?.should be_false
+    end
 
-  it "raises an error for rectangular matrices" do
-    -> {
-      Matrix[[1], [2], [3]].singular?
-    }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "returns false for an empty 0x0 matrix" do
+      Matrix.empty(0,0).singular?.should be_false
+    end
 
-    -> {
-      Matrix.empty(3,0).singular?
-    }.should raise_error(Matrix::ErrDimensionMismatch)
-  end
+    it "raises an error for rectangular matrices" do
+      -> {
+        Matrix[[1], [2], [3]].singular?
+      }.should raise_error(Matrix::ErrDimensionMismatch)
+
+      -> {
+        Matrix.empty(3,0).singular?
+      }.should raise_error(Matrix::ErrDimensionMismatch)
+    end
 
+  end
 end
diff --git a/spec/ruby/library/matrix/square_spec.rb b/spec/ruby/library/matrix/square_spec.rb
index 25d2d1ad9c..e678f1c702 100644
--- a/spec/ruby/library/matrix/square_spec.rb
+++ b/spec/ruby/library/matrix/square_spec.rb
@@ -1,28 +1,31 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#square?" do
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true when the Matrix is square" do
-    Matrix[ [1,2], [2,4] ].square?.should be_true
-    Matrix[ [100,3,5], [9.5, 4.9, 8], [2,0,77] ].square?.should be_true
-  end
+  describe "Matrix#square?" do
 
-  it "returns true when the Matrix has only one element" do
-    Matrix[ [9] ].square?.should be_true
-  end
+    it "returns true when the Matrix is square" do
+      Matrix[ [1,2], [2,4] ].square?.should be_true
+      Matrix[ [100,3,5], [9.5, 4.9, 8], [2,0,77] ].square?.should be_true
+    end
 
-  it "returns false when the Matrix is rectangular" do
-    Matrix[ [1, 2] ].square?.should be_false
-  end
+    it "returns true when the Matrix has only one element" do
+      Matrix[ [9] ].square?.should be_true
+    end
 
-  it "returns false when the Matrix is rectangular" do
-    Matrix[ [1], [2] ].square?.should be_false
-  end
+    it "returns false when the Matrix is rectangular" do
+      Matrix[ [1, 2] ].square?.should be_false
+    end
+
+    it "returns false when the Matrix is rectangular" do
+      Matrix[ [1], [2] ].square?.should be_false
+    end
 
-  it "returns handles empty matrices" do
-    Matrix[].square?.should be_true
-    Matrix[[]].square?.should be_false
-    Matrix.columns([[]]).square?.should be_false
+    it "returns handles empty matrices" do
+      Matrix[].square?.should be_true
+      Matrix[[]].square?.should be_false
+      Matrix.columns([[]]).square?.should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/symmetric_spec.rb b/spec/ruby/library/matrix/symmetric_spec.rb
index 6f2a99276a..9eed28ac0d 100644
--- a/spec/ruby/library/matrix/symmetric_spec.rb
+++ b/spec/ruby/library/matrix/symmetric_spec.rb
@@ -1,29 +1,32 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.symmetric?" do
-  it "returns true for a symmetric Matrix" do
-    Matrix[[1, 2, Complex(0, 3)], [2, 4, 5], [Complex(0, 3), 5, 6]].symmetric?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for a 0x0 empty matrix" do
-    Matrix.empty.symmetric?.should be_true
-  end
+  describe "Matrix.symmetric?" do
+    it "returns true for a symmetric Matrix" do
+      Matrix[[1, 2, Complex(0, 3)], [2, 4, 5], [Complex(0, 3), 5, 6]].symmetric?.should be_true
+    end
 
-  it "returns false for an asymmetric Matrix" do
-    Matrix[[1, 2],[-2, 1]].symmetric?.should be_false
-  end
+    it "returns true for a 0x0 empty matrix" do
+      Matrix.empty.symmetric?.should be_true
+    end
+
+    it "returns false for an asymmetric Matrix" do
+      Matrix[[1, 2],[-2, 1]].symmetric?.should be_false
+    end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.symmetric?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.symmetric?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/t_spec.rb b/spec/ruby/library/matrix/t_spec.rb
index 6f1a5178e0..6eb54371ee 100644
--- a/spec/ruby/library/matrix/t_spec.rb
+++ b/spec/ruby/library/matrix/t_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/transpose'
 
-describe "Matrix#transpose" do
-  it_behaves_like :matrix_transpose, :t
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/transpose'
+
+  describe "Matrix#transpose" do
+    it_behaves_like :matrix_transpose, :t
+  end
 end
diff --git a/spec/ruby/library/matrix/to_a_spec.rb b/spec/ruby/library/matrix/to_a_spec.rb
index b5d55c5d67..0222a663ac 100644
--- a/spec/ruby/library/matrix/to_a_spec.rb
+++ b/spec/ruby/library/matrix/to_a_spec.rb
@@ -1,11 +1,14 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#to_a" do
-  it "returns the array of arrays that describe the rows of the matrix" do
-    Matrix[].to_a.should == []
-    Matrix[[]].to_a.should == [[]]
-    Matrix[[1]].to_a.should == [[1]]
-    Matrix[[1, 2], [3, 4]].to_a.should == [[1, 2],[3, 4]]
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix#to_a" do
+    it "returns the array of arrays that describe the rows of the matrix" do
+      Matrix[].to_a.should == []
+      Matrix[[]].to_a.should == [[]]
+      Matrix[[1]].to_a.should == [[1]]
+      Matrix[[1, 2], [3, 4]].to_a.should == [[1, 2],[3, 4]]
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/to_s_spec.rb b/spec/ruby/library/matrix/to_s_spec.rb
index f529fe3bcd..7d38655e0d 100644
--- a/spec/ruby/library/matrix/to_s_spec.rb
+++ b/spec/ruby/library/matrix/to_s_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix#to_s" do
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Matrix#to_s" do
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/matrix/tr_spec.rb b/spec/ruby/library/matrix/tr_spec.rb
index e17bd790d7..bbf274bb5e 100644
--- a/spec/ruby/library/matrix/tr_spec.rb
+++ b/spec/ruby/library/matrix/tr_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'shared/trace'
-require 'matrix'
 
-describe "Matrix#tr" do
-  it_behaves_like :trace, :tr
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/trace'
+  require 'matrix'
+
+  describe "Matrix#tr" do
+    it_behaves_like :trace, :tr
+  end
 end
diff --git a/spec/ruby/library/matrix/trace_spec.rb b/spec/ruby/library/matrix/trace_spec.rb
index 290e7cb1f7..ac6ce7927d 100644
--- a/spec/ruby/library/matrix/trace_spec.rb
+++ b/spec/ruby/library/matrix/trace_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'shared/trace'
-require 'matrix'
 
-describe "Matrix#trace" do
-  it_behaves_like :trace, :trace
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/trace'
+  require 'matrix'
+
+  describe "Matrix#trace" do
+    it_behaves_like :trace, :trace
+  end
 end
diff --git a/spec/ruby/library/matrix/transpose_spec.rb b/spec/ruby/library/matrix/transpose_spec.rb
index 79600dd439..d7f495b946 100644
--- a/spec/ruby/library/matrix/transpose_spec.rb
+++ b/spec/ruby/library/matrix/transpose_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/transpose'
 
-describe "Matrix#transpose" do
-  it_behaves_like :matrix_transpose, :transpose
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/transpose'
+
+  describe "Matrix#transpose" do
+    it_behaves_like :matrix_transpose, :transpose
+  end
 end
diff --git a/spec/ruby/library/matrix/unit_spec.rb b/spec/ruby/library/matrix/unit_spec.rb
index 6a41d729c7..439e0d616b 100644
--- a/spec/ruby/library/matrix/unit_spec.rb
+++ b/spec/ruby/library/matrix/unit_spec.rb
@@ -1,6 +1,9 @@
 require_relative '../../spec_helper'
-require_relative 'shared/identity'
 
-describe "Matrix.unit" do
-  it_behaves_like :matrix_identity, :unit
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/identity'
+
+  describe "Matrix.unit" do
+    it_behaves_like :matrix_identity, :unit
+  end
 end
diff --git a/spec/ruby/library/matrix/unitary_spec.rb b/spec/ruby/library/matrix/unitary_spec.rb
index af4b2bb442..b579cb244d 100644
--- a/spec/ruby/library/matrix/unitary_spec.rb
+++ b/spec/ruby/library/matrix/unitary_spec.rb
@@ -1,33 +1,36 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.unitary?" do
-  it "returns false for non unitary matrices" do
-    Matrix[[0, 1], [1, 2]].should_not.unitary?
-    Matrix[[0, Complex(0, 2)], [Complex(0, 2), 0]].should_not.unitary?
-    Matrix[[1, 1, 0], [0, 1, 1], [1, 0, 1]].should_not.unitary?
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for unitary matrices" do
-    Matrix[[0, Complex(0, 1)], [Complex(0, 1), 0]].should.unitary?
-  end
+  describe "Matrix.unitary?" do
+    it "returns false for non unitary matrices" do
+      Matrix[[0, 1], [1, 2]].should_not.unitary?
+      Matrix[[0, Complex(0, 2)], [Complex(0, 2), 0]].should_not.unitary?
+      Matrix[[1, 1, 0], [0, 1, 1], [1, 0, 1]].should_not.unitary?
+    end
 
-  version_is((Matrix::const_defined?(:VERSION) ? Matrix::VERSION : "0.1.0"), "0.3.0") do
-    it "returns true for unitary matrices with a Complex and a negative #imag" do
-      Matrix[[0, Complex(0, 1)], [Complex(0, -1), 0]].should.unitary?
+    it "returns true for unitary matrices" do
+      Matrix[[0, Complex(0, 1)], [Complex(0, 1), 0]].should.unitary?
+    end
+
+    version_is((Matrix::const_defined?(:VERSION) ? Matrix::VERSION : "0.1.0"), "0.3.0") do
+      it "returns true for unitary matrices with a Complex and a negative #imag" do
+        Matrix[[0, Complex(0, 1)], [Complex(0, -1), 0]].should.unitary?
+      end
     end
-  end
 
-  it "raises an error for rectangular matrices" do
-    [
-      Matrix[[0], [0]],
-      Matrix[[0, 0]],
-      Matrix.empty(0, 2),
-      Matrix.empty(2, 0),
-    ].each do |rectangular_matrix|
-      -> {
-        rectangular_matrix.unitary?
-      }.should raise_error(Matrix::ErrDimensionMismatch)
+    it "raises an error for rectangular matrices" do
+      [
+        Matrix[[0], [0]],
+        Matrix[[0, 0]],
+        Matrix.empty(0, 2),
+        Matrix.empty(2, 0),
+      ].each do |rectangular_matrix|
+        -> {
+          rectangular_matrix.unitary?
+        }.should raise_error(Matrix::ErrDimensionMismatch)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/upper_triangular_spec.rb b/spec/ruby/library/matrix/upper_triangular_spec.rb
index 2514294a80..cc2aeb7233 100644
--- a/spec/ruby/library/matrix/upper_triangular_spec.rb
+++ b/spec/ruby/library/matrix/upper_triangular_spec.rb
@@ -1,24 +1,27 @@
 require_relative '../../spec_helper'
-require 'matrix'
 
-describe "Matrix.upper_triangular?" do
-  it "returns true for an upper triangular Matrix" do
-    Matrix[[1, 2, 3], [0, 2, 3], [0, 0, 3]].upper_triangular?.should be_true
-    Matrix.diagonal([1, 2, 3]).upper_triangular?.should be_true
-    Matrix[[1, 2], [0, 2], [0, 0], [0, 0]].upper_triangular?.should be_true
-    Matrix[[1, 2, 3, 4], [0, 2, 3, 4]].upper_triangular?.should be_true
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns false for a non upper triangular square Matrix" do
-    Matrix[[0, 0], [1, 0]].upper_triangular?.should be_false
-    Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].upper_triangular?.should be_false
-    Matrix[[0, 0], [0, 0], [0, 0], [0, 1]].upper_triangular?.should be_false
-    Matrix[[0, 0, 0, 0], [1, 0, 0, 0]].upper_triangular?.should be_false
-  end
+  describe "Matrix.upper_triangular?" do
+    it "returns true for an upper triangular Matrix" do
+      Matrix[[1, 2, 3], [0, 2, 3], [0, 0, 3]].upper_triangular?.should be_true
+      Matrix.diagonal([1, 2, 3]).upper_triangular?.should be_true
+      Matrix[[1, 2], [0, 2], [0, 0], [0, 0]].upper_triangular?.should be_true
+      Matrix[[1, 2, 3, 4], [0, 2, 3, 4]].upper_triangular?.should be_true
+    end
+
+    it "returns false for a non upper triangular square Matrix" do
+      Matrix[[0, 0], [1, 0]].upper_triangular?.should be_false
+      Matrix[[1, 2, 3], [1, 2, 3], [1, 2, 3]].upper_triangular?.should be_false
+      Matrix[[0, 0], [0, 0], [0, 0], [0, 1]].upper_triangular?.should be_false
+      Matrix[[0, 0, 0, 0], [1, 0, 0, 0]].upper_triangular?.should be_false
+    end
 
-  it "returns true for an empty matrix" do
-    Matrix.empty(3,0).upper_triangular?.should be_true
-    Matrix.empty(0,3).upper_triangular?.should be_true
-    Matrix.empty(0,0).upper_triangular?.should be_true
+    it "returns true for an empty matrix" do
+      Matrix.empty(3,0).upper_triangular?.should be_true
+      Matrix.empty(0,3).upper_triangular?.should be_true
+      Matrix.empty(0,0).upper_triangular?.should be_true
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/vector/cross_product_spec.rb b/spec/ruby/library/matrix/vector/cross_product_spec.rb
index c2698ade4c..88523824cd 100644
--- a/spec/ruby/library/matrix/vector/cross_product_spec.rb
+++ b/spec/ruby/library/matrix/vector/cross_product_spec.rb
@@ -1,14 +1,17 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Vector#cross_product" do
-  it "returns the cross product of a vector" do
-    Vector[1, 2, 3].cross_product(Vector[0, -4, 5]).should == Vector[22, -5, -4]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Vector#cross_product" do
+    it "returns the cross product of a vector" do
+      Vector[1, 2, 3].cross_product(Vector[0, -4, 5]).should == Vector[22, -5, -4]
+    end
 
-  it "raises an error unless both vectors have dimension 3" do
-    -> {
-      Vector[1, 2, 3].cross_product(Vector[0, -4])
-    }.should raise_error(Vector::ErrDimensionMismatch)
+    it "raises an error unless both vectors have dimension 3" do
+      -> {
+        Vector[1, 2, 3].cross_product(Vector[0, -4])
+      }.should raise_error(Vector::ErrDimensionMismatch)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/vector/each2_spec.rb b/spec/ruby/library/matrix/vector/each2_spec.rb
index 10d2fc404d..bdd6966472 100644
--- a/spec/ruby/library/matrix/vector/each2_spec.rb
+++ b/spec/ruby/library/matrix/vector/each2_spec.rb
@@ -1,49 +1,52 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Vector.each2" do
-  before :all do
-    @v = Vector[1, 2, 3]
-    @v2 = Vector[4, 5, 6]
-  end
-
-  it "requires one argument" do
-    -> { @v.each2(@v2, @v2){} }.should raise_error(ArgumentError)
-    -> { @v.each2(){} }.should raise_error(ArgumentError)
-  end
-
-  describe "given one argument" do
-    it "accepts an Array argument" do
-      a = []
-      @v.each2([7, 8, 9]){|x, y| a << x << y}
-      a.should == [1, 7, 2, 8, 3, 9]
-    end
-
-    it "raises a DimensionMismatch error if the Vector size is different" do
-      -> { @v.each2(Vector[1,2]){}     }.should raise_error(Vector::ErrDimensionMismatch)
-      -> { @v.each2(Vector[1,2,3,4]){} }.should raise_error(Vector::ErrDimensionMismatch)
-    end
-
-    it "yields arguments in sequence" do
-      a = []
-      @v.each2(@v2){|first, second| a << [first, second]}
-      a.should == [[1, 4], [2, 5], [3, 6]]
-    end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-    it "yield arguments in pairs" do
-      a = []
-      @v.each2(@v2){|*pair| a << pair}
-      a.should == [[1, 4], [2, 5], [3, 6]]
+  describe "Vector.each2" do
+    before :all do
+      @v = Vector[1, 2, 3]
+      @v2 = Vector[4, 5, 6]
     end
 
-    it "returns self when given a block" do
-      @v.each2(@v2){}.should equal(@v)
+    it "requires one argument" do
+      -> { @v.each2(@v2, @v2){} }.should raise_error(ArgumentError)
+      -> { @v.each2(){} }.should raise_error(ArgumentError)
     end
 
-    it "returns an enumerator if no block given" do
-      enum = @v.each2(@v2)
-      enum.should be_an_instance_of(Enumerator)
-      enum.to_a.should == [[1, 4], [2, 5], [3, 6]]
+    describe "given one argument" do
+      it "accepts an Array argument" do
+        a = []
+        @v.each2([7, 8, 9]){|x, y| a << x << y}
+        a.should == [1, 7, 2, 8, 3, 9]
+      end
+
+      it "raises a DimensionMismatch error if the Vector size is different" do
+        -> { @v.each2(Vector[1,2]){}     }.should raise_error(Vector::ErrDimensionMismatch)
+        -> { @v.each2(Vector[1,2,3,4]){} }.should raise_error(Vector::ErrDimensionMismatch)
+      end
+
+      it "yields arguments in sequence" do
+        a = []
+        @v.each2(@v2){|first, second| a << [first, second]}
+        a.should == [[1, 4], [2, 5], [3, 6]]
+      end
+
+      it "yield arguments in pairs" do
+        a = []
+        @v.each2(@v2){|*pair| a << pair}
+        a.should == [[1, 4], [2, 5], [3, 6]]
+      end
+
+      it "returns self when given a block" do
+        @v.each2(@v2){}.should equal(@v)
+      end
+
+      it "returns an enumerator if no block given" do
+        enum = @v.each2(@v2)
+        enum.should be_an_instance_of(Enumerator)
+        enum.to_a.should == [[1, 4], [2, 5], [3, 6]]
+      end
     end
   end
 end
diff --git a/spec/ruby/library/matrix/vector/eql_spec.rb b/spec/ruby/library/matrix/vector/eql_spec.rb
index eb2451b550..fa086bd33a 100644
--- a/spec/ruby/library/matrix/vector/eql_spec.rb
+++ b/spec/ruby/library/matrix/vector/eql_spec.rb
@@ -1,16 +1,19 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Vector#eql?" do
-  before do
-    @vector = Vector[1, 2, 3, 4, 5]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns true for self" do
-    @vector.eql?(@vector).should be_true
-  end
+  describe "Vector#eql?" do
+    before do
+      @vector = Vector[1, 2, 3, 4, 5]
+    end
+
+    it "returns true for self" do
+      @vector.eql?(@vector).should be_true
+    end
 
-  it "returns false when there are a pair corresponding elements which are not equal in the sense of Kernel#eql?" do
-    @vector.eql?(Vector[1, 2, 3, 4, 5.0]).should be_false
+    it "returns false when there are a pair corresponding elements which are not equal in the sense of Kernel#eql?" do
+      @vector.eql?(Vector[1, 2, 3, 4, 5.0]).should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/vector/inner_product_spec.rb b/spec/ruby/library/matrix/vector/inner_product_spec.rb
index 1cf8771e04..95dc4806b5 100644
--- a/spec/ruby/library/matrix/vector/inner_product_spec.rb
+++ b/spec/ruby/library/matrix/vector/inner_product_spec.rb
@@ -1,22 +1,25 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Vector#inner_product" do
-  it "returns the inner product of a vector" do
-    Vector[1, 2, 3].inner_product(Vector[0, -4, 5]).should == 7
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
 
-  it "returns 0 for empty vectors" do
-    Vector[].inner_product(Vector[]).should == 0
-  end
+  describe "Vector#inner_product" do
+    it "returns the inner product of a vector" do
+      Vector[1, 2, 3].inner_product(Vector[0, -4, 5]).should == 7
+    end
 
-  it "raises an error for mismatched vectors" do
-    -> {
-      Vector[1, 2, 3].inner_product(Vector[0, -4])
-    }.should raise_error(Vector::ErrDimensionMismatch)
-  end
+    it "returns 0 for empty vectors" do
+      Vector[].inner_product(Vector[]).should == 0
+    end
+
+    it "raises an error for mismatched vectors" do
+      -> {
+        Vector[1, 2, 3].inner_product(Vector[0, -4])
+      }.should raise_error(Vector::ErrDimensionMismatch)
+    end
 
-  it "uses the conjugate of its argument" do
-    Vector[Complex(1,2)].inner_product(Vector[Complex(3,4)]).should == Complex(11, 2)
+    it "uses the conjugate of its argument" do
+      Vector[Complex(1,2)].inner_product(Vector[Complex(3,4)]).should == Complex(11, 2)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/vector/normalize_spec.rb b/spec/ruby/library/matrix/vector/normalize_spec.rb
index 527c9260de..7345e11fa4 100644
--- a/spec/ruby/library/matrix/vector/normalize_spec.rb
+++ b/spec/ruby/library/matrix/vector/normalize_spec.rb
@@ -1,18 +1,21 @@
 require_relative '../../../spec_helper'
-require 'matrix'
 
-describe "Vector#normalize" do
-  it "returns a normalized copy of the vector" do
-    x = 0.2672612419124244
-    Vector[1, 2, 3].normalize.should == Vector[x, x * 2, x * 3]
-  end
+ruby_version_is ""..."3.1" do
+  require 'matrix'
+
+  describe "Vector#normalize" do
+    it "returns a normalized copy of the vector" do
+      x = 0.2672612419124244
+      Vector[1, 2, 3].normalize.should == Vector[x, x * 2, x * 3]
+    end
 
-  it "raises an error for zero vectors" do
-    -> {
-      Vector[].normalize
-    }.should raise_error(Vector::ZeroVectorError)
-    -> {
-      Vector[0, 0, 0].normalize
-    }.should raise_error(Vector::ZeroVectorError)
+    it "raises an error for zero vectors" do
+      -> {
+        Vector[].normalize
+      }.should raise_error(Vector::ZeroVectorError)
+      -> {
+        Vector[0, 0, 0].normalize
+      }.should raise_error(Vector::ZeroVectorError)
+    end
   end
 end
diff --git a/spec/ruby/library/matrix/zero_spec.rb b/spec/ruby/library/matrix/zero_spec.rb
index 68e8567c26..80162a03d0 100644
--- a/spec/ruby/library/matrix/zero_spec.rb
+++ b/spec/ruby/library/matrix/zero_spec.rb
@@ -1,52 +1,55 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require 'matrix'
 
-describe "Matrix.zero" do
-  it "returns an object of type Matrix" do
-    Matrix.zero(3).should be_kind_of(Matrix)
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'fixtures/classes'
+  require 'matrix'
 
-  it "creates a n x n matrix" do
-    m3 = Matrix.zero(3)
-    m3.row_size.should == 3
-    m3.column_size.should == 3
+  describe "Matrix.zero" do
+    it "returns an object of type Matrix" do
+      Matrix.zero(3).should be_kind_of(Matrix)
+    end
 
-    m8 = Matrix.zero(8)
-    m8.row_size.should == 8
-    m8.column_size.should == 8
-  end
+    it "creates a n x n matrix" do
+      m3 = Matrix.zero(3)
+      m3.row_size.should == 3
+      m3.column_size.should == 3
 
-  it "initializes all cells to 0" do
-    size = 10
-    m = Matrix.zero(size)
+      m8 = Matrix.zero(8)
+      m8.row_size.should == 8
+      m8.column_size.should == 8
+    end
 
-    (0...size).each do |i|
-      (0...size).each do |j|
-        m[i, j].should == 0
+    it "initializes all cells to 0" do
+      size = 10
+      m = Matrix.zero(size)
+
+      (0...size).each do |i|
+        (0...size).each do |j|
+          m[i, j].should == 0
+        end
       end
     end
-  end
 
-  describe "for a subclass of Matrix" do
-    it "returns an instance of that subclass" do
-      MatrixSub.zero(3).should be_an_instance_of(MatrixSub)
+    describe "for a subclass of Matrix" do
+      it "returns an instance of that subclass" do
+        MatrixSub.zero(3).should be_an_instance_of(MatrixSub)
+      end
     end
   end
-end
 
-describe "Matrix.zero?" do
-  it "returns true for empty matrices" do
-    Matrix.empty.should.zero?
-    Matrix.empty(3,0).should.zero?
-    Matrix.empty(0,3).should.zero?
-  end
+  describe "Matrix.zero?" do
+    it "returns true for empty matrices" do
+      Matrix.empty.should.zero?
+      Matrix.empty(3,0).should.zero?
+      Matrix.empty(0,3).should.zero?
+    end
 
-  it "returns true for matrices with zero entries" do
-    Matrix.zero(2,3).should.zero?
-  end
+    it "returns true for matrices with zero entries" do
+      Matrix.zero(2,3).should.zero?
+    end
 
-  it "returns false for matrices with non zero entries" do
-    Matrix[[1]].should_not.zero?
+    it "returns false for matrices with non zero entries" do
+      Matrix[[1]].should_not.zero?
+    end
   end
 end
diff --git a/spec/ruby/library/net/FTPError_spec.rb b/spec/ruby/library/net/FTPError_spec.rb
index 0c31b65dcc..84128511db 100644
--- a/spec/ruby/library/net/FTPError_spec.rb
+++ b/spec/ruby/library/net/FTPError_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../spec_helper'
-require 'net/ftp'
 
-describe "Net::FTPError" do
-  it "is an Exception" do
-    Net::FTPError.should < Exception
+ruby_version_is ""..."3.1" do
+  require 'net/ftp'
+
+  describe "Net::FTPError" do
+    it "is an Exception" do
+      Net::FTPError.should < Exception
+    end
   end
 end
diff --git a/spec/ruby/library/net/FTPPermError_spec.rb b/spec/ruby/library/net/FTPPermError_spec.rb
index b43e12c503..0da35e7d82 100644
--- a/spec/ruby/library/net/FTPPermError_spec.rb
+++ b/spec/ruby/library/net/FTPPermError_spec.rb
@@ -1,12 +1,15 @@
 require_relative '../../spec_helper'
-require 'net/ftp'
 
-describe "Net::FTPPermError" do
-  it "is an Exception" do
-    Net::FTPPermError.should < Exception
-  end
+ruby_version_is ""..."3.1" do
+  require 'net/ftp'
+
+  describe "Net::FTPPermError" do
+    it "is an Exception" do
+      Net::FTPPermError.should < Exception
+    end
 
-  it "is a subclass of Net::FTPError" do
-    Net::FTPPermError.should < Net::FTPError
+    it "is a subclass of Net::FTPError" do
+      Net::FTPPermError.should < Net::FTPError
+    end
   end
 end
diff --git a/spec/ruby/library/net/FTPProtoError_spec.rb b/spec/ruby/library/net/FTPProtoError_spec.rb
index e7abbc0dd8..20e30dd2dd 100644
--- a/spec/ruby/library/net/FTPProtoError_spec.rb
+++ b/spec/ruby/library/net/FTPProtoError_spec.rb
@@ -1,12 +1,15 @@
 require_relative '../../spec_helper'
-require 'net/ftp'
 
-describe "Net::FTPProtoError" do
-  it "is an Exception" do
-    Net::FTPProtoError.should < Exception
-  end
+ruby_version_is ""..."3.1" do
+  require 'net/ftp'
+
+  describe "Net::FTPProtoError" do
+    it "is an Exception" do
+      Net::FTPProtoError.should < Exception
+    end
 
-  it "is a subclass of Net::FTPError" do
-    Net::FTPPermError.should < Net::FTPError
+    it "is a subclass of Net::FTPError" do
+      Net::FTPPermError.should < Net::FTPError
+    end
   end
 end
diff --git a/spec/ruby/library/net/FTPReplyError_spec.rb b/spec/ruby/library/net/FTPReplyError_spec.rb
index fcc7501fc1..cc774aabe5 100644
--- a/spec/ruby/library/net/FTPReplyError_spec.rb
+++ b/spec/ruby/library/net/FTPReplyError_spec.rb
@@ -1,12 +1,15 @@
 require_relative '../../spec_helper'
-require 'net/ftp'
 
-describe "Net::FTPReplyError" do
-  it "is an Exception" do
-    Net::FTPReplyError.should < Exception
-  end
+ruby_version_is ""..."3.1" do
+  require 'net/ftp'
+
+  describe "Net::FTPReplyError" do
+    it "is an Exception" do
+      Net::FTPReplyError.should < Exception
+    end
 
-  it "is a subclass of Net::FTPError" do
-    Net::FTPPermError.should < Net::FTPError
+    it "is a subclass of Net::FTPError" do
+      Net::FTPPermError.should < Net::FTPError
+    end
   end
 end
diff --git a/spec/ruby/library/net/FTPTempError_spec.rb b/spec/ruby/library/net/FTPTempError_spec.rb
index f4b045dfb5..e2fbdfd842 100644
--- a/spec/ruby/library/net/FTPTempError_spec.rb
+++ b/spec/ruby/library/net/FTPTempError_spec.rb
@@ -1,12 +1,15 @@
 require_relative '../../spec_helper'
-require 'net/ftp'
 
-describe "Net::FTPTempError" do
-  it "is an Exception" do
-    Net::FTPTempError.should < Exception
-  end
+ruby_version_is ""..."3.1" do
+  require 'net/ftp'
+
+  describe "Net::FTPTempError" do
+    it "is an Exception" do
+      Net::FTPTempError.should < Exception
+    end
 
-  it "is a subclass of Net::FTPError" do
-    Net::FTPPermError.should < Net::FTPError
+    it "is a subclass of Net::FTPError" do
+      Net::FTPPermError.should < Net::FTPError
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/abort_spec.rb b/spec/ruby/library/net/ftp/abort_spec.rb
index 57651468d8..ebdfed4b16 100644
--- a/spec/ruby/library/net/ftp/abort_spec.rb
+++ b/spec/ruby/library/net/ftp/abort_spec.rb
@@ -1,62 +1,65 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#abort" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#abort" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the ABOR command to the server" do
-    -> { @ftp.abort }.should_not raise_error
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "ignores the response" do
-    @ftp.abort
-    @ftp.last_response.should == "220 Dummy FTP Server ready!\n"
-  end
+    it "sends the ABOR command to the server" do
+      -> { @ftp.abort }.should_not raise_error
+    end
 
-  it "returns the full response" do
-    @ftp.abort.should == "226 Closing data connection. (ABOR)\n"
-  end
+    it "ignores the response" do
+      @ftp.abort
+      @ftp.last_response.should == "220 Dummy FTP Server ready!\n"
+    end
 
-  it "does not raise any error when the response code is 225" do
-    @server.should_receive(:abor).and_respond("225 Data connection open; no transfer in progress.")
-    -> { @ftp.abort }.should_not raise_error
-  end
+    it "returns the full response" do
+      @ftp.abort.should == "226 Closing data connection. (ABOR)\n"
+    end
 
-  it "does not raise any error when the response code is 226" do
-    @server.should_receive(:abor).and_respond("226 Closing data connection.")
-    -> { @ftp.abort }.should_not raise_error
-  end
+    it "does not raise any error when the response code is 225" do
+      @server.should_receive(:abor).and_respond("225 Data connection open; no transfer in progress.")
+      -> { @ftp.abort }.should_not raise_error
+    end
 
-  it "raises a Net::FTPProtoError when the response code is 500" do
-    @server.should_receive(:abor).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
-  end
+    it "does not raise any error when the response code is 226" do
+      @server.should_receive(:abor).and_respond("226 Closing data connection.")
+      -> { @ftp.abort }.should_not raise_error
+    end
 
-  it "raises a Net::FTPProtoError when the response code is 501" do
-    @server.should_receive(:abor).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
-  end
+    it "raises a Net::FTPProtoError when the response code is 500" do
+      @server.should_receive(:abor).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
+    end
 
-  it "raises a Net::FTPProtoError when the response code is 502" do
-    @server.should_receive(:abor).and_respond("502 Command not implemented.")
-    -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
-  end
+    it "raises a Net::FTPProtoError when the response code is 501" do
+      @server.should_receive(:abor).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
+    end
+
+    it "raises a Net::FTPProtoError when the response code is 502" do
+      @server.should_receive(:abor).and_respond("502 Command not implemented.")
+      -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
+    end
 
-  it "raises a Net::FTPProtoError when the response code is 421" do
-    @server.should_receive(:abor).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
+    it "raises a Net::FTPProtoError when the response code is 421" do
+      @server.should_receive(:abor).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.abort }.should raise_error(Net::FTPProtoError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/acct_spec.rb b/spec/ruby/library/net/ftp/acct_spec.rb
index d8068dc81e..a960ae20a4 100644
--- a/spec/ruby/library/net/ftp/acct_spec.rb
+++ b/spec/ruby/library/net/ftp/acct_spec.rb
@@ -1,58 +1,61 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#acct" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "writes the ACCT command to the server" do
-    @ftp.acct("my_account")
-    @ftp.last_response.should == "230 User 'my_account' logged in, proceed. (ACCT)\n"
-  end
-
-  it "returns nil" do
-    @ftp.acct("my_account").should == nil
-  end
-
-  it "does not raise any error when the response code is 230" do
-    @server.should_receive(:acct).and_respond("230 User logged in, proceed.")
-    -> { @ftp.acct("my_account") }.should_not raise_error
-  end
-
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:acct).and_respond("530 Not logged in.")
-    -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:acct).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:acct).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 503" do
-    @server.should_receive(:acct).and_respond("503 Bad sequence of commands.")
-    -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:acct).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.acct("my_account") }.should raise_error(Net::FTPTempError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#acct" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "writes the ACCT command to the server" do
+      @ftp.acct("my_account")
+      @ftp.last_response.should == "230 User 'my_account' logged in, proceed. (ACCT)\n"
+    end
+
+    it "returns nil" do
+      @ftp.acct("my_account").should == nil
+    end
+
+    it "does not raise any error when the response code is 230" do
+      @server.should_receive(:acct).and_respond("230 User logged in, proceed.")
+      -> { @ftp.acct("my_account") }.should_not raise_error
+    end
+
+    it "raises a Net::FTPPermError when the response code is 530" do
+      @server.should_receive(:acct).and_respond("530 Not logged in.")
+      -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:acct).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:acct).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 503" do
+      @server.should_receive(:acct).and_respond("503 Bad sequence of commands.")
+      -> { @ftp.acct("my_account") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:acct).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.acct("my_account") }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/binary_spec.rb b/spec/ruby/library/net/ftp/binary_spec.rb
index 60e312a673..da7e2d6c14 100644
--- a/spec/ruby/library/net/ftp/binary_spec.rb
+++ b/spec/ruby/library/net/ftp/binary_spec.rb
@@ -1,24 +1,27 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#binary" do
-  it "returns true when self is in binary mode" do
-    ftp = Net::FTP.new
-    ftp.binary.should be_true
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-    ftp.binary = false
-    ftp.binary.should be_false
+  describe "Net::FTP#binary" do
+    it "returns true when self is in binary mode" do
+      ftp = Net::FTP.new
+      ftp.binary.should be_true
+
+      ftp.binary = false
+      ftp.binary.should be_false
+    end
   end
-end
 
-describe "Net::FTP#binary=" do
-  it "sets self to binary mode when passed true" do
-    ftp = Net::FTP.new
+  describe "Net::FTP#binary=" do
+    it "sets self to binary mode when passed true" do
+      ftp = Net::FTP.new
 
-    ftp.binary = true
-    ftp.binary.should be_true
+      ftp.binary = true
+      ftp.binary.should be_true
 
-    ftp.binary = false
-    ftp.binary.should be_false
+      ftp.binary = false
+      ftp.binary.should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/chdir_spec.rb b/spec/ruby/library/net/ftp/chdir_spec.rb
index 4c10fa78b4..741c3c845e 100644
--- a/spec/ruby/library/net/ftp/chdir_spec.rb
+++ b/spec/ruby/library/net/ftp/chdir_spec.rb
@@ -1,99 +1,102 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#chdir" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#chdir" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    describe "when switching to the parent directory" do
+      it "sends the 'CDUP' command to the server" do
+        @ftp.chdir("..")
+        @ftp.last_response.should == "200 Command okay. (CDUP)\n"
+      end
+
+      it "returns nil" do
+        @ftp.chdir("..").should be_nil
+      end
+
+      it "does not raise a Net::FTPPermError when the response code is 500" do
+        @server.should_receive(:cdup).and_respond("500 Syntax error, command unrecognized.")
+        -> { @ftp.chdir("..") }.should_not raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:cdup).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:cdup).and_respond("502 Command not implemented.")
+        -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:cdup).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.chdir("..") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:cdup).and_respond("530 Not logged in.")
+        -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 550" do
+        @server.should_receive(:cdup).and_respond("550 Requested action not taken.")
+        -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      end
+    end
 
-  describe "when switching to the parent directory" do
-    it "sends the 'CDUP' command to the server" do
-      @ftp.chdir("..")
-      @ftp.last_response.should == "200 Command okay. (CDUP)\n"
+    it "writes the 'CWD' command with the passed directory to the socket" do
+      @ftp.chdir("test")
+      @ftp.last_response.should == "200 Command okay. (CWD test)\n"
     end
 
     it "returns nil" do
-      @ftp.chdir("..").should be_nil
+      @ftp.chdir("test").should be_nil
     end
 
-    it "does not raise a Net::FTPPermError when the response code is 500" do
-      @server.should_receive(:cdup).and_respond("500 Syntax error, command unrecognized.")
-      -> { @ftp.chdir("..") }.should_not raise_error(Net::FTPPermError)
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:cwd).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
     end
 
     it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:cdup).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      @server.should_receive(:cwd).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
     end
 
     it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:cdup).and_respond("502 Command not implemented.")
-      -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      @server.should_receive(:cwd).and_respond("502 Command not implemented.")
+      -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
     end
 
     it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:cdup).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.chdir("..") }.should raise_error(Net::FTPTempError)
+      @server.should_receive(:cwd).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.chdir("test") }.should raise_error(Net::FTPTempError)
     end
 
     it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:cdup).and_respond("530 Not logged in.")
-      -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      @server.should_receive(:cwd).and_respond("530 Not logged in.")
+      -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
     end
 
     it "raises a Net::FTPPermError when the response code is 550" do
-      @server.should_receive(:cdup).and_respond("550 Requested action not taken.")
-      -> { @ftp.chdir("..") }.should raise_error(Net::FTPPermError)
+      @server.should_receive(:cwd).and_respond("550 Requested action not taken.")
+      -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
     end
   end
-
-  it "writes the 'CWD' command with the passed directory to the socket" do
-    @ftp.chdir("test")
-    @ftp.last_response.should == "200 Command okay. (CWD test)\n"
-  end
-
-  it "returns nil" do
-    @ftp.chdir("test").should be_nil
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:cwd).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:cwd).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:cwd).and_respond("502 Command not implemented.")
-    -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:cwd).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.chdir("test") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:cwd).and_respond("530 Not logged in.")
-    -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:cwd).and_respond("550 Requested action not taken.")
-    -> { @ftp.chdir("test") }.should raise_error(Net::FTPPermError)
-  end
 end
diff --git a/spec/ruby/library/net/ftp/close_spec.rb b/spec/ruby/library/net/ftp/close_spec.rb
index 95c72b29ed..49cdf4dea7 100644
--- a/spec/ruby/library/net/ftp/close_spec.rb
+++ b/spec/ruby/library/net/ftp/close_spec.rb
@@ -1,30 +1,33 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#close" do
-  before :each do
-    @socket = mock("Socket")
-    @socket.stub!(:closed?).and_return(false)
-    @socket.stub!(:read_timeout).and_return(60)
-    @socket.stub!(:read_timeout=).and_return(3)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-    @ftp = Net::FTP.new
-    @ftp.instance_variable_set(:@sock, @socket)
-  end
+  describe "Net::FTP#close" do
+    before :each do
+      @socket = mock("Socket")
+      @socket.stub!(:closed?).and_return(false)
+      @socket.stub!(:read_timeout).and_return(60)
+      @socket.stub!(:read_timeout=).and_return(3)
 
-  it "closes the socket" do
-    @socket.should_receive(:close)
-    @ftp.close.should be_nil
-  end
+      @ftp = Net::FTP.new
+      @ftp.instance_variable_set(:@sock, @socket)
+    end
 
-  it "does not try to close the socket if it has already been closed" do
-    @socket.should_receive(:closed?).and_return(true)
-    @socket.should_not_receive(:close)
-    @ftp.close.should be_nil
-  end
+    it "closes the socket" do
+      @socket.should_receive(:close)
+      @ftp.close.should be_nil
+    end
+
+    it "does not try to close the socket if it has already been closed" do
+      @socket.should_receive(:closed?).and_return(true)
+      @socket.should_not_receive(:close)
+      @ftp.close.should be_nil
+    end
 
-  it "does not try to close the socket if it is nil" do
-    @ftp.instance_variable_set(:@sock, nil)
-    @ftp.close.should be_nil
+    it "does not try to close the socket if it is nil" do
+      @ftp.instance_variable_set(:@sock, nil)
+      @ftp.close.should be_nil
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/closed_spec.rb b/spec/ruby/library/net/ftp/closed_spec.rb
index 1f3e69b0c1..a81917090a 100644
--- a/spec/ruby/library/net/ftp/closed_spec.rb
+++ b/spec/ruby/library/net/ftp/closed_spec.rb
@@ -1,21 +1,24 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#closed?" do
-  before :each do
-    @socket = mock("Socket")
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-    @ftp = Net::FTP.new
-    @ftp.instance_variable_set(:@sock, @socket)
-  end
+  describe "Net::FTP#closed?" do
+    before :each do
+      @socket = mock("Socket")
 
-  it "returns true when the socket is closed" do
-    @socket.should_receive(:closed?).and_return(true)
-    @ftp.closed?.should be_true
-  end
+      @ftp = Net::FTP.new
+      @ftp.instance_variable_set(:@sock, @socket)
+    end
+
+    it "returns true when the socket is closed" do
+      @socket.should_receive(:closed?).and_return(true)
+      @ftp.closed?.should be_true
+    end
 
-  it "returns true when the socket is nil" do
-    @ftp.instance_variable_set(:@sock, nil)
-    @ftp.closed?.should be_true
+    it "returns true when the socket is nil" do
+      @ftp.instance_variable_set(:@sock, nil)
+      @ftp.closed?.should be_true
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/connect_spec.rb b/spec/ruby/library/net/ftp/connect_spec.rb
index 9ee9bcd2c6..b45e46c530 100644
--- a/spec/ruby/library/net/ftp/connect_spec.rb
+++ b/spec/ruby/library/net/ftp/connect_spec.rb
@@ -1,49 +1,52 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-# TODO: Add specs for using the SOCKSSocket
-describe "Net::FTP#connect" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-  end
-
-  after :each do
-    @server.connect_message = nil
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "tries to connect to the FTP Server on the given host and port" do
-    -> { @ftp.connect(@server.hostname, @server.server_port) }.should_not raise_error
-  end
-
-  it "returns nil" do
-    @ftp.connect(@server.hostname, @server.server_port).should be_nil
-  end
-
-  it "prints a small debug line when in debug mode" do
-    @ftp.debug_mode = true
-    -> { @ftp.connect(@server.hostname, @server.server_port) }.should output(/#{"connect: "}#{@server.hostname}#{", "}#{@server.server_port}#{"\\nget: 220 Dummy FTP Server ready!"}/)
-    @ftp.debug_mode = false
-  end
-
-  it "does not raise any error when the response code is 220" do
-    @server.connect_message = "220 Dummy FTP Server ready!"
-    -> { @ftp.connect(@server.hostname, @server.server_port) }.should_not raise_error
-  end
-
-  it "raises a Net::FTPReplyError when the response code is 120" do
-    @server.connect_message = "120 Service ready in nnn minutes."
-    -> { @ftp.connect(@server.hostname, @server.server_port) }.should raise_error(Net::FTPReplyError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.connect_message = "421 Service not available, closing control connection."
-    -> { @ftp.connect(@server.hostname, @server.server_port) }.should raise_error(Net::FTPTempError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  # TODO: Add specs for using the SOCKSSocket
+  describe "Net::FTP#connect" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+    end
+
+    after :each do
+      @server.connect_message = nil
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "tries to connect to the FTP Server on the given host and port" do
+      -> { @ftp.connect(@server.hostname, @server.server_port) }.should_not raise_error
+    end
+
+    it "returns nil" do
+      @ftp.connect(@server.hostname, @server.server_port).should be_nil
+    end
+
+    it "prints a small debug line when in debug mode" do
+      @ftp.debug_mode = true
+      -> { @ftp.connect(@server.hostname, @server.server_port) }.should output(/#{"connect: "}#{@server.hostname}#{", "}#{@server.server_port}#{"\\nget: 220 Dummy FTP Server ready!"}/)
+      @ftp.debug_mode = false
+    end
+
+    it "does not raise any error when the response code is 220" do
+      @server.connect_message = "220 Dummy FTP Server ready!"
+      -> { @ftp.connect(@server.hostname, @server.server_port) }.should_not raise_error
+    end
+
+    it "raises a Net::FTPReplyError when the response code is 120" do
+      @server.connect_message = "120 Service ready in nnn minutes."
+      -> { @ftp.connect(@server.hostname, @server.server_port) }.should raise_error(Net::FTPReplyError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.connect_message = "421 Service not available, closing control connection."
+      -> { @ftp.connect(@server.hostname, @server.server_port) }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/debug_mode_spec.rb b/spec/ruby/library/net/ftp/debug_mode_spec.rb
index f49da55ed1..46d207bbea 100644
--- a/spec/ruby/library/net/ftp/debug_mode_spec.rb
+++ b/spec/ruby/library/net/ftp/debug_mode_spec.rb
@@ -1,23 +1,26 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#debug_mode" do
-  it "returns true when self is in debug mode" do
-    ftp = Net::FTP.new
-    ftp.debug_mode.should be_false
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-    ftp.debug_mode = true
-    ftp.debug_mode.should be_true
+  describe "Net::FTP#debug_mode" do
+    it "returns true when self is in debug mode" do
+      ftp = Net::FTP.new
+      ftp.debug_mode.should be_false
+
+      ftp.debug_mode = true
+      ftp.debug_mode.should be_true
+    end
   end
-end
 
-describe "Net::FTP#debug_mode=" do
-  it "sets self into debug mode when passed true" do
-    ftp = Net::FTP.new
-    ftp.debug_mode = true
-    ftp.debug_mode.should be_true
+  describe "Net::FTP#debug_mode=" do
+    it "sets self into debug mode when passed true" do
+      ftp = Net::FTP.new
+      ftp.debug_mode = true
+      ftp.debug_mode.should be_true
 
-    ftp.debug_mode = false
-    ftp.debug_mode.should be_false
+      ftp.debug_mode = false
+      ftp.debug_mode.should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/default_passive_spec.rb b/spec/ruby/library/net/ftp/default_passive_spec.rb
index 30eb8f9da2..9348d3294d 100644
--- a/spec/ruby/library/net/ftp/default_passive_spec.rb
+++ b/spec/ruby/library/net/ftp/default_passive_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#default_passive" do
-  it "is true by default" do
-    ruby_exe(fixture(__FILE__, "default_passive.rb")).should == "true\ntrue\n"
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+
+  describe "Net::FTP#default_passive" do
+    it "is true by default" do
+      ruby_exe(fixture(__FILE__, "default_passive.rb")).should == "true\ntrue\n"
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/delete_spec.rb b/spec/ruby/library/net/ftp/delete_spec.rb
index cf8f9332e2..43bfcc1541 100644
--- a/spec/ruby/library/net/ftp/delete_spec.rb
+++ b/spec/ruby/library/net/ftp/delete_spec.rb
@@ -1,59 +1,62 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#delete" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the DELE command with the passed filename to the server" do
-    @ftp.delete("test.file")
-    @ftp.last_response.should == "250 Requested file action okay, completed. (DELE test.file)\n"
-  end
-
-  it "raises a Net::FTPTempError when the response code is 450" do
-    @server.should_receive(:dele).and_respond("450 Requested file action not taken.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:dele).and_respond("550 Requested action not taken.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:dele).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:dele).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:dele).and_respond("502 Command not implemented.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:dele).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:dele).and_respond("530 Not logged in.")
-    -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#delete" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the DELE command with the passed filename to the server" do
+      @ftp.delete("test.file")
+      @ftp.last_response.should == "250 Requested file action okay, completed. (DELE test.file)\n"
+    end
+
+    it "raises a Net::FTPTempError when the response code is 450" do
+      @server.should_receive(:dele).and_respond("450 Requested file action not taken.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:dele).and_respond("550 Requested action not taken.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:dele).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:dele).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:dele).and_respond("502 Command not implemented.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:dele).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 530" do
+      @server.should_receive(:dele).and_respond("530 Not logged in.")
+      -> { @ftp.delete("test.file") }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/dir_spec.rb b/spec/ruby/library/net/ftp/dir_spec.rb
index 47ac7b8d9b..dce50a5ac5 100644
--- a/spec/ruby/library/net/ftp/dir_spec.rb
+++ b/spec/ruby/library/net/ftp/dir_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/list'
 
-describe "Net::FTP#dir" do
-  it_behaves_like :net_ftp_list, :dir
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/list'
+
+  describe "Net::FTP#dir" do
+    it_behaves_like :net_ftp_list, :dir
+  end
 end
diff --git a/spec/ruby/library/net/ftp/get_spec.rb b/spec/ruby/library/net/ftp/get_spec.rb
index c4672b55a5..892b30061c 100644
--- a/spec/ruby/library/net/ftp/get_spec.rb
+++ b/spec/ruby/library/net/ftp/get_spec.rb
@@ -1,21 +1,24 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/gettextfile'
-require_relative 'shared/getbinaryfile'
 
-describe "Net::FTP#get (binary mode)" do
-  before :each do
-    @binary_mode = true
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/gettextfile'
+  require_relative 'shared/getbinaryfile'
 
-  it_behaves_like :net_ftp_getbinaryfile, :get
-end
+  describe "Net::FTP#get (binary mode)" do
+    before :each do
+      @binary_mode = true
+    end
 
-describe "Net::FTP#get (text mode)" do
-  before :each do
-    @binary_mode = false
+    it_behaves_like :net_ftp_getbinaryfile, :get
   end
 
-  it_behaves_like :net_ftp_gettextfile, :get
+  describe "Net::FTP#get (text mode)" do
+    before :each do
+      @binary_mode = false
+    end
+
+    it_behaves_like :net_ftp_gettextfile, :get
+  end
 end
diff --git a/spec/ruby/library/net/ftp/getbinaryfile_spec.rb b/spec/ruby/library/net/ftp/getbinaryfile_spec.rb
index 155851b53c..c5abdd67e7 100644
--- a/spec/ruby/library/net/ftp/getbinaryfile_spec.rb
+++ b/spec/ruby/library/net/ftp/getbinaryfile_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/getbinaryfile'
 
-describe "Net::FTP#getbinaryfile" do
-  it_behaves_like :net_ftp_getbinaryfile, :getbinaryfile
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/getbinaryfile'
+
+  describe "Net::FTP#getbinaryfile" do
+    it_behaves_like :net_ftp_getbinaryfile, :getbinaryfile
+  end
 end
diff --git a/spec/ruby/library/net/ftp/getdir_spec.rb b/spec/ruby/library/net/ftp/getdir_spec.rb
index eea35ac130..8f6fca5bfb 100644
--- a/spec/ruby/library/net/ftp/getdir_spec.rb
+++ b/spec/ruby/library/net/ftp/getdir_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'shared/pwd'
 
-describe "Net::FTP#getdir" do
-  it_behaves_like :net_ftp_pwd, :getdir
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'shared/pwd'
+
+  describe "Net::FTP#getdir" do
+    it_behaves_like :net_ftp_pwd, :getdir
+  end
 end
diff --git a/spec/ruby/library/net/ftp/gettextfile_spec.rb b/spec/ruby/library/net/ftp/gettextfile_spec.rb
index 79395ae009..e272ae73b1 100644
--- a/spec/ruby/library/net/ftp/gettextfile_spec.rb
+++ b/spec/ruby/library/net/ftp/gettextfile_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/gettextfile'
 
-describe "Net::FTP#gettextfile" do
-  it_behaves_like :net_ftp_gettextfile, :gettextfile
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/gettextfile'
+
+  describe "Net::FTP#gettextfile" do
+    it_behaves_like :net_ftp_gettextfile, :gettextfile
+  end
 end
diff --git a/spec/ruby/library/net/ftp/help_spec.rb b/spec/ruby/library/net/ftp/help_spec.rb
index d2e9fe7ee8..9b15f42ede 100644
--- a/spec/ruby/library/net/ftp/help_spec.rb
+++ b/spec/ruby/library/net/ftp/help_spec.rb
@@ -1,66 +1,69 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#help" do
-  def with_connection
-    yield
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+  describe "Net::FTP#help" do
+    def with_connection
+      yield
+    end
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "writes the HELP command to the server" do
-    @ftp.help
-    @ftp.last_response.should == "211 System status, or system help reply. (HELP)\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "returns the server's response" do
-    @ftp.help.should == "211 System status, or system help reply. (HELP)\n"
-  end
+    it "writes the HELP command to the server" do
+      @ftp.help
+      @ftp.last_response.should == "211 System status, or system help reply. (HELP)\n"
+    end
 
-  it "writes the HELP command with an optional parameter to the socket" do
-    @ftp.help("some parameter").should == "211 System status, or system help reply. (HELP some parameter)\n"
-  end
+    it "returns the server's response" do
+      @ftp.help.should == "211 System status, or system help reply. (HELP)\n"
+    end
 
-  it "does not raise any error when the response code is 211" do
-    @server.should_receive(:help).and_respond("211 System status, or system help reply.")
-    -> { @ftp.help }.should_not raise_error
-  end
+    it "writes the HELP command with an optional parameter to the socket" do
+      @ftp.help("some parameter").should == "211 System status, or system help reply. (HELP some parameter)\n"
+    end
 
-  it "does not raise any error when the response code is 214" do
-    @server.should_receive(:help).and_respond("214 Help message.")
-    -> { @ftp.help }.should_not raise_error
-  end
+    it "does not raise any error when the response code is 211" do
+      @server.should_receive(:help).and_respond("211 System status, or system help reply.")
+      -> { @ftp.help }.should_not raise_error
+    end
 
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:help).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.help }.should raise_error(Net::FTPPermError)
-  end
+    it "does not raise any error when the response code is 214" do
+      @server.should_receive(:help).and_respond("214 Help message.")
+      -> { @ftp.help }.should_not raise_error
+    end
 
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:help).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.help }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:help).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.help }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:help).and_respond("502 Command not implemented.")
-    -> { @ftp.help }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:help).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.help }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:help).and_respond("502 Command not implemented.")
+      -> { @ftp.help }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:help).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.help }.should raise_error(Net::FTPTempError)
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:help).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.help }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/initialize_spec.rb b/spec/ruby/library/net/ftp/initialize_spec.rb
index a2f64ddb1b..80f71a9161 100644
--- a/spec/ruby/library/net/ftp/initialize_spec.rb
+++ b/spec/ruby/library/net/ftp/initialize_spec.rb
@@ -1,402 +1,405 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-
-describe "Net::FTP#initialize" do
-  before :each do
-    @ftp = Net::FTP.allocate
-    @ftp.stub!(:connect)
-    @port_args = []
-    @port_args << 21
-  end
 
-  it "is private" do
-    Net::FTP.should have_private_instance_method(:initialize)
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-  it "sets self into binary mode" do
-    @ftp.binary.should be_nil
-    @ftp.send(:initialize)
-    @ftp.binary.should be_true
-  end
-
-  it "sets self into active mode" do
-    @ftp.passive.should be_nil
-    @ftp.send(:initialize)
-    @ftp.passive.should be_false
-  end
+  describe "Net::FTP#initialize" do
+    before :each do
+      @ftp = Net::FTP.allocate
+      @ftp.stub!(:connect)
+      @port_args = []
+      @port_args << 21
+    end
 
-  it "sets self into non-debug mode" do
-    @ftp.debug_mode.should be_nil
-    @ftp.send(:initialize)
-    @ftp.debug_mode.should be_false
-  end
+    it "is private" do
+      Net::FTP.should have_private_instance_method(:initialize)
+    end
 
-  it "sets self to not resume file uploads/downloads" do
-    @ftp.resume.should be_nil
-    @ftp.send(:initialize)
-    @ftp.resume.should be_false
-  end
+    it "sets self into binary mode" do
+      @ftp.binary.should be_nil
+      @ftp.send(:initialize)
+      @ftp.binary.should be_true
+    end
 
-  describe "when passed no arguments" do
-    it "does not try to connect" do
-      @ftp.should_not_receive(:connect)
+    it "sets self into active mode" do
+      @ftp.passive.should be_nil
       @ftp.send(:initialize)
+      @ftp.passive.should be_false
     end
-  end
 
-  describe "when passed host" do
-    it "tries to connect to the passed host" do
-      @ftp.should_receive(:connect).with("localhost", *@port_args)
-      @ftp.send(:initialize, "localhost")
+    it "sets self into non-debug mode" do
+      @ftp.debug_mode.should be_nil
+      @ftp.send(:initialize)
+      @ftp.debug_mode.should be_false
     end
-  end
 
-  describe "when passed host, user" do
-    it "tries to connect to the passed host" do
-      @ftp.should_receive(:connect).with("localhost", *@port_args)
-      @ftp.send(:initialize, "localhost")
+    it "sets self to not resume file uploads/downloads" do
+      @ftp.resume.should be_nil
+      @ftp.send(:initialize)
+      @ftp.resume.should be_false
     end
 
-    it "tries to login with the passed username" do
-      @ftp.should_receive(:login).with("rubyspec", nil, nil)
-      @ftp.send(:initialize, "localhost", "rubyspec")
+    describe "when passed no arguments" do
+      it "does not try to connect" do
+        @ftp.should_not_receive(:connect)
+        @ftp.send(:initialize)
+      end
     end
-  end
 
-  describe "when passed host, user, password" do
-    it "tries to connect to the passed host" do
-      @ftp.should_receive(:connect).with("localhost", *@port_args)
-      @ftp.send(:initialize, "localhost")
+    describe "when passed host" do
+      it "tries to connect to the passed host" do
+        @ftp.should_receive(:connect).with("localhost", *@port_args)
+        @ftp.send(:initialize, "localhost")
+      end
     end
 
-    it "tries to login with the passed username and password" do
-      @ftp.should_receive(:login).with("rubyspec", "rocks", nil)
-      @ftp.send(:initialize, "localhost", "rubyspec", "rocks")
+    describe "when passed host, user" do
+      it "tries to connect to the passed host" do
+        @ftp.should_receive(:connect).with("localhost", *@port_args)
+        @ftp.send(:initialize, "localhost")
+      end
+
+      it "tries to login with the passed username" do
+        @ftp.should_receive(:login).with("rubyspec", nil, nil)
+        @ftp.send(:initialize, "localhost", "rubyspec")
+      end
     end
-  end
 
-  describe "when passed host, user" do
-    it "tries to connect to the passed host" do
-      @ftp.should_receive(:connect).with("localhost", *@port_args)
-      @ftp.send(:initialize, "localhost")
+    describe "when passed host, user, password" do
+      it "tries to connect to the passed host" do
+        @ftp.should_receive(:connect).with("localhost", *@port_args)
+        @ftp.send(:initialize, "localhost")
+      end
+
+      it "tries to login with the passed username and password" do
+        @ftp.should_receive(:login).with("rubyspec", "rocks", nil)
+        @ftp.send(:initialize, "localhost", "rubyspec", "rocks")
+      end
     end
 
-    it "tries to login with the passed username, password and account" do
-      @ftp.should_receive(:login).with("rubyspec", "rocks", "account")
-      @ftp.send(:initialize, "localhost", "rubyspec", "rocks", "account")
+    describe "when passed host, user" do
+      it "tries to connect to the passed host" do
+        @ftp.should_receive(:connect).with("localhost", *@port_args)
+        @ftp.send(:initialize, "localhost")
+      end
+
+      it "tries to login with the passed username, password and account" do
+        @ftp.should_receive(:login).with("rubyspec", "rocks", "account")
+        @ftp.send(:initialize, "localhost", "rubyspec", "rocks", "account")
+      end
     end
-  end
 
-  before :each do
-    @ftp.stub!(:login)
-  end
+    before :each do
+      @ftp.stub!(:login)
+    end
 
-  describe 'when the host' do
-    describe 'is set' do
-      describe 'and port option' do
-        describe 'is set' do
-          it 'tries to connect to the host on the specified port' do
-            options = mock('ftp initialize options')
-            options.should_receive(:to_hash).and_return({ port: 8080 })
-            @ftp.should_receive(:connect).with('localhost', 8080)
+    describe 'when the host' do
+      describe 'is set' do
+        describe 'and port option' do
+          describe 'is set' do
+            it 'tries to connect to the host on the specified port' do
+              options = mock('ftp initialize options')
+              options.should_receive(:to_hash).and_return({ port: 8080 })
+              @ftp.should_receive(:connect).with('localhost', 8080)
 
-            @ftp.send(:initialize, 'localhost', options)
+              @ftp.send(:initialize, 'localhost', options)
+            end
           end
-        end
 
-        describe 'is not set' do
-          it 'tries to connect to the host without a port' do
-            @ftp.should_receive(:connect).with("localhost", *@port_args)
+          describe 'is not set' do
+            it 'tries to connect to the host without a port' do
+              @ftp.should_receive(:connect).with("localhost", *@port_args)
 
-            @ftp.send(:initialize, 'localhost')
+              @ftp.send(:initialize, 'localhost')
+            end
           end
         end
-      end
 
-      describe 'when the username option' do
-        describe 'is set' do
-          describe 'and the password option' do
-            describe 'is set' do
-              describe 'and the account option' do
-                describe 'is set' do
-                  it 'tries to log in with the supplied parameters' do
-                    options = mock('ftp initialize options')
-                    options.should_receive(:to_hash).and_return({ username: 'a', password: 'topsecret', account: 'b' })
-                    @ftp.should_receive(:login).with('a', 'topsecret', 'b')
-
-                    @ftp.send(:initialize, 'localhost', options)
+        describe 'when the username option' do
+          describe 'is set' do
+            describe 'and the password option' do
+              describe 'is set' do
+                describe 'and the account option' do
+                  describe 'is set' do
+                    it 'tries to log in with the supplied parameters' do
+                      options = mock('ftp initialize options')
+                      options.should_receive(:to_hash).and_return({ username: 'a', password: 'topsecret', account: 'b' })
+                      @ftp.should_receive(:login).with('a', 'topsecret', 'b')
+
+                      @ftp.send(:initialize, 'localhost', options)
+                    end
                   end
-                end
 
-                describe 'is unset' do
-                  it 'tries to log in with the supplied parameters' do
-                    options = mock('ftp initialize options')
-                    options.should_receive(:to_hash).and_return({ username: 'a', password: 'topsecret' })
-                    @ftp.should_receive(:login).with('a', 'topsecret', nil)
+                  describe 'is unset' do
+                    it 'tries to log in with the supplied parameters' do
+                      options = mock('ftp initialize options')
+                      options.should_receive(:to_hash).and_return({ username: 'a', password: 'topsecret' })
+                      @ftp.should_receive(:login).with('a', 'topsecret', nil)
 
-                    @ftp.send(:initialize, 'localhost', options)
+                      @ftp.send(:initialize, 'localhost', options)
+                    end
                   end
                 end
               end
-            end
 
-            describe 'is unset' do
-              describe 'and the account option' do
-                describe 'is set' do
-                  it 'tries to log in with the supplied parameters' do
-                    options = mock('ftp initialize options')
-                    options.should_receive(:to_hash).and_return({ username: 'a', account: 'b' })
-                    @ftp.should_receive(:login).with('a', nil, 'b')
+              describe 'is unset' do
+                describe 'and the account option' do
+                  describe 'is set' do
+                    it 'tries to log in with the supplied parameters' do
+                      options = mock('ftp initialize options')
+                      options.should_receive(:to_hash).and_return({ username: 'a', account: 'b' })
+                      @ftp.should_receive(:login).with('a', nil, 'b')
 
-                    @ftp.send(:initialize, 'localhost', options)
+                      @ftp.send(:initialize, 'localhost', options)
+                    end
                   end
-                end
 
-                describe 'is unset' do
-                  it 'tries to log in with the supplied parameters' do
-                    options = mock('ftp initialize options')
-                    options.should_receive(:to_hash).and_return({ username: 'a'})
-                    @ftp.should_receive(:login).with('a', nil, nil)
+                  describe 'is unset' do
+                    it 'tries to log in with the supplied parameters' do
+                      options = mock('ftp initialize options')
+                      options.should_receive(:to_hash).and_return({ username: 'a'})
+                      @ftp.should_receive(:login).with('a', nil, nil)
 
-                    @ftp.send(:initialize, 'localhost', options)
+                      @ftp.send(:initialize, 'localhost', options)
+                    end
                   end
                 end
               end
             end
           end
-        end
 
-        describe 'is not set' do
-          it 'does not try to log in' do
-            options = mock('ftp initialize options')
-            options.should_receive(:to_hash).and_return({})
-            @ftp.should_not_receive(:login)
+          describe 'is not set' do
+            it 'does not try to log in' do
+              options = mock('ftp initialize options')
+              options.should_receive(:to_hash).and_return({})
+              @ftp.should_not_receive(:login)
 
-            @ftp.send(:initialize, 'localhost', options)
+              @ftp.send(:initialize, 'localhost', options)
+            end
           end
         end
       end
-    end
 
-    describe 'is unset' do
-      it 'does not try to connect' do
-        @ftp.should_not_receive(:connect)
+      describe 'is unset' do
+        it 'does not try to connect' do
+          @ftp.should_not_receive(:connect)
 
-        @ftp.send(:initialize)
-      end
+          @ftp.send(:initialize)
+        end
 
-      it 'does not try to log in' do
-        @ftp.should_not_receive(:login)
+        it 'does not try to log in' do
+          @ftp.should_not_receive(:login)
 
-        @ftp.send(:initialize)
+          @ftp.send(:initialize)
+        end
       end
     end
-  end
 
-  describe 'when the passive option' do
-    describe 'is set' do
-      describe 'to true' do
-        it 'sets passive to true' do
-          options = mock('ftp initialize options')
-          options.should_receive(:to_hash).and_return({ passive: true })
+    describe 'when the passive option' do
+      describe 'is set' do
+        describe 'to true' do
+          it 'sets passive to true' do
+            options = mock('ftp initialize options')
+            options.should_receive(:to_hash).and_return({ passive: true })
 
-          @ftp.send(:initialize, nil, options)
-          @ftp.passive.should == true
+            @ftp.send(:initialize, nil, options)
+            @ftp.passive.should == true
+          end
+        end
+
+        describe 'to false' do
+          it 'sets passive to false' do
+            options = mock('ftp initialize options')
+            options.should_receive(:to_hash).and_return({ passive: false })
+
+            @ftp.send(:initialize, nil, options)
+            @ftp.passive.should == false
+          end
         end
       end
 
-      describe 'to false' do
+      describe 'is unset' do
         it 'sets passive to false' do
-          options = mock('ftp initialize options')
-          options.should_receive(:to_hash).and_return({ passive: false })
-
-          @ftp.send(:initialize, nil, options)
+          @ftp.send(:initialize)
           @ftp.passive.should == false
         end
       end
     end
 
-    describe 'is unset' do
-      it 'sets passive to false' do
-        @ftp.send(:initialize)
-        @ftp.passive.should == false
-      end
-    end
-  end
+    describe 'when the debug_mode option' do
+      describe 'is set' do
+        describe 'to true' do
+          it 'sets debug_mode to true' do
+            options = mock('ftp initialize options')
+            options.should_receive(:to_hash).and_return({ debug_mode: true })
 
-  describe 'when the debug_mode option' do
-    describe 'is set' do
-      describe 'to true' do
-        it 'sets debug_mode to true' do
-          options = mock('ftp initialize options')
-          options.should_receive(:to_hash).and_return({ debug_mode: true })
+            @ftp.send(:initialize, nil, options)
+            @ftp.debug_mode.should == true
+          end
+        end
 
-          @ftp.send(:initialize, nil, options)
-          @ftp.debug_mode.should == true
+        describe 'to false' do
+          it 'sets debug_mode to false' do
+            options = mock('ftp initialize options')
+            options.should_receive(:to_hash).and_return({ debug_mode: false })
+
+            @ftp.send(:initialize, nil, options)
+            @ftp.debug_mode.should == false
+          end
         end
       end
 
-      describe 'to false' do
+      describe 'is unset' do
         it 'sets debug_mode to false' do
-          options = mock('ftp initialize options')
-          options.should_receive(:to_hash).and_return({ debug_mode: false })
-
-          @ftp.send(:initialize, nil, options)
+          @ftp.send(:initialize)
           @ftp.debug_mode.should == false
         end
       end
     end
 
-    describe 'is unset' do
-      it 'sets debug_mode to false' do
-        @ftp.send(:initialize)
-        @ftp.debug_mode.should == false
-      end
-    end
-  end
-
-  describe 'when the open_timeout option' do
-    describe 'is set' do
-      it 'sets open_timeout to the specified value' do
-        options = mock('ftp initialize options')
-        options.should_receive(:to_hash).and_return({ open_timeout: 42 })
+    describe 'when the open_timeout option' do
+      describe 'is set' do
+        it 'sets open_timeout to the specified value' do
+          options = mock('ftp initialize options')
+          options.should_receive(:to_hash).and_return({ open_timeout: 42 })
 
-        @ftp.send(:initialize, nil, options)
-        @ftp.open_timeout.should == 42
+          @ftp.send(:initialize, nil, options)
+          @ftp.open_timeout.should == 42
+        end
       end
-    end
 
-    describe 'is not set' do
-      it 'sets open_timeout to nil' do
-        @ftp.send(:initialize)
-        @ftp.open_timeout.should == nil
+      describe 'is not set' do
+        it 'sets open_timeout to nil' do
+          @ftp.send(:initialize)
+          @ftp.open_timeout.should == nil
+        end
       end
     end
-  end
 
-  describe 'when the read_timeout option' do
-    describe 'is set' do
-      it 'sets read_timeout to the specified value' do
-        options = mock('ftp initialize options')
-        options.should_receive(:to_hash).and_return({ read_timeout: 100 })
+    describe 'when the read_timeout option' do
+      describe 'is set' do
+        it 'sets read_timeout to the specified value' do
+          options = mock('ftp initialize options')
+          options.should_receive(:to_hash).and_return({ read_timeout: 100 })
 
-        @ftp.send(:initialize, nil, options)
-        @ftp.read_timeout.should == 100
+          @ftp.send(:initialize, nil, options)
+          @ftp.read_timeout.should == 100
+        end
       end
-    end
 
-    describe 'is not set' do
-      it 'sets read_timeout to the default value' do
-        @ftp.send(:initialize)
-        @ftp.read_timeout.should == 60
+      describe 'is not set' do
+        it 'sets read_timeout to the default value' do
+          @ftp.send(:initialize)
+          @ftp.read_timeout.should == 60
+        end
       end
     end
-  end
 
-  describe 'when the ssl_handshake_timeout option' do
-    describe 'is set' do
-      it 'sets ssl_handshake_timeout to the specified value' do
-        options = mock('ftp initialize options')
-        options.should_receive(:to_hash).and_return({ ssl_handshake_timeout: 23 })
+    describe 'when the ssl_handshake_timeout option' do
+      describe 'is set' do
+        it 'sets ssl_handshake_timeout to the specified value' do
+          options = mock('ftp initialize options')
+          options.should_receive(:to_hash).and_return({ ssl_handshake_timeout: 23 })
 
-        @ftp.send(:initialize, nil, options)
-        @ftp.ssl_handshake_timeout.should == 23
+          @ftp.send(:initialize, nil, options)
+          @ftp.ssl_handshake_timeout.should == 23
+        end
       end
-    end
 
-    describe 'is not set' do
-      it 'sets ssl_handshake_timeout to nil' do
-        @ftp.send(:initialize)
-        @ftp.ssl_handshake_timeout.should == nil
+      describe 'is not set' do
+        it 'sets ssl_handshake_timeout to nil' do
+          @ftp.send(:initialize)
+          @ftp.ssl_handshake_timeout.should == nil
+        end
       end
     end
-  end
 
-  describe 'when the ssl option' do
-    describe 'is set' do
-      describe "and the ssl option's value is true" do
-        it 'initializes ssl_context to a blank SSLContext object' do
-          options = mock('ftp initialize options')
-          options.should_receive(:to_hash).and_return({ ssl: true })
+    describe 'when the ssl option' do
+      describe 'is set' do
+        describe "and the ssl option's value is true" do
+          it 'initializes ssl_context to a blank SSLContext object' do
+            options = mock('ftp initialize options')
+            options.should_receive(:to_hash).and_return({ ssl: true })
 
-          ssl_context = OpenSSL::SSL::SSLContext.allocate
-          ssl_context.stub!(:set_params)
+            ssl_context = OpenSSL::SSL::SSLContext.allocate
+            ssl_context.stub!(:set_params)
 
-          OpenSSL::SSL::SSLContext.should_receive(:new).and_return(ssl_context)
-          ssl_context.should_receive(:set_params).with({})
+            OpenSSL::SSL::SSLContext.should_receive(:new).and_return(ssl_context)
+            ssl_context.should_receive(:set_params).with({})
 
-          @ftp.send(:initialize, nil, options)
-          @ftp.instance_variable_get(:@ssl_context).should == ssl_context
+            @ftp.send(:initialize, nil, options)
+            @ftp.instance_variable_get(:@ssl_context).should == ssl_context
+          end
         end
-      end
 
-      describe "and the ssl option's value is a hash" do
-        it 'initializes ssl_context to a configured SSLContext object' do
-          options = mock('ftp initialize options')
-          options.should_receive(:to_hash).and_return({ ssl: {key: 'value'} })
+        describe "and the ssl option's value is a hash" do
+          it 'initializes ssl_context to a configured SSLContext object' do
+            options = mock('ftp initialize options')
+            options.should_receive(:to_hash).and_return({ ssl: {key: 'value'} })
 
-          ssl_context = OpenSSL::SSL::SSLContext.allocate
-          ssl_context.stub!(:set_params)
+            ssl_context = OpenSSL::SSL::SSLContext.allocate
+            ssl_context.stub!(:set_params)
 
-          OpenSSL::SSL::SSLContext.should_receive(:new).and_return(ssl_context)
-          ssl_context.should_receive(:set_params).with({key: 'value'})
+            OpenSSL::SSL::SSLContext.should_receive(:new).and_return(ssl_context)
+            ssl_context.should_receive(:set_params).with({key: 'value'})
 
-          @ftp.send(:initialize, nil, options)
-          @ftp.instance_variable_get(:@ssl_context).should == ssl_context
+            @ftp.send(:initialize, nil, options)
+            @ftp.instance_variable_get(:@ssl_context).should == ssl_context
+          end
         end
-      end
 
-      describe 'and private_data_connection' do
-        describe 'is set' do
-          it 'sets private_data_connection to that value' do
-            options = mock('ftp initialize options')
-            options.should_receive(:to_hash).and_return({ ssl: true, private_data_connection: 'true' })
+        describe 'and private_data_connection' do
+          describe 'is set' do
+            it 'sets private_data_connection to that value' do
+              options = mock('ftp initialize options')
+              options.should_receive(:to_hash).and_return({ ssl: true, private_data_connection: 'true' })
 
-            @ftp.send(:initialize, nil, options)
-            @ftp.instance_variable_get(:@private_data_connection).should == 'true'
+              @ftp.send(:initialize, nil, options)
+              @ftp.instance_variable_get(:@private_data_connection).should == 'true'
+            end
           end
-        end
 
-        describe 'is not set' do
-          it 'sets private_data_connection to nil' do
-            options = mock('ftp initialize options')
-            options.should_receive(:to_hash).and_return({ ssl: true })
+          describe 'is not set' do
+            it 'sets private_data_connection to nil' do
+              options = mock('ftp initialize options')
+              options.should_receive(:to_hash).and_return({ ssl: true })
 
-            @ftp.send(:initialize, nil, options)
-            @ftp.instance_variable_get(:@private_data_connection).should == true
+              @ftp.send(:initialize, nil, options)
+              @ftp.instance_variable_get(:@private_data_connection).should == true
+            end
           end
         end
       end
-    end
 
-    describe 'is not set' do
-      it 'sets ssl_context to nil' do
-        options = mock('ftp initialize options')
-        options.should_receive(:to_hash).and_return({})
+      describe 'is not set' do
+        it 'sets ssl_context to nil' do
+          options = mock('ftp initialize options')
+          options.should_receive(:to_hash).and_return({})
 
-        @ftp.send(:initialize, nil, options)
-        @ftp.instance_variable_get(:@ssl_context).should == nil
-      end
+          @ftp.send(:initialize, nil, options)
+          @ftp.instance_variable_get(:@ssl_context).should == nil
+        end
 
-      describe 'private_data_connection' do
-        describe 'is set' do
-          it 'raises an ArgumentError' do
-            options = mock('ftp initialize options')
-            options.should_receive(:to_hash).and_return({ private_data_connection: true })
+        describe 'private_data_connection' do
+          describe 'is set' do
+            it 'raises an ArgumentError' do
+              options = mock('ftp initialize options')
+              options.should_receive(:to_hash).and_return({ private_data_connection: true })
 
-            -> {
-              @ftp.send(:initialize, nil, options)
-            }.should raise_error(ArgumentError, /private_data_connection can be set to true only when ssl is enabled/)
+              -> {
+                @ftp.send(:initialize, nil, options)
+              }.should raise_error(ArgumentError, /private_data_connection can be set to true only when ssl is enabled/)
+            end
           end
-        end
 
-        describe 'is not set' do
-          it 'sets private_data_connection to false' do
-            options = mock('ftp initialize options')
-            options.should_receive(:to_hash).and_return({})
+          describe 'is not set' do
+            it 'sets private_data_connection to false' do
+              options = mock('ftp initialize options')
+              options.should_receive(:to_hash).and_return({})
 
-            @ftp.send(:initialize, nil, options)
-            @ftp.instance_variable_get(:@private_data_connection).should == false
+              @ftp.send(:initialize, nil, options)
+              @ftp.instance_variable_get(:@private_data_connection).should == false
+            end
           end
         end
       end
diff --git a/spec/ruby/library/net/ftp/last_response_code_spec.rb b/spec/ruby/library/net/ftp/last_response_code_spec.rb
index 3eb20f7ad8..86f2b9a695 100644
--- a/spec/ruby/library/net/ftp/last_response_code_spec.rb
+++ b/spec/ruby/library/net/ftp/last_response_code_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'shared/last_response_code'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#last_response_code" do
-  it_behaves_like :net_ftp_last_response_code, :last_response_code
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'shared/last_response_code'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#last_response_code" do
+    it_behaves_like :net_ftp_last_response_code, :last_response_code
+  end
 end
diff --git a/spec/ruby/library/net/ftp/last_response_spec.rb b/spec/ruby/library/net/ftp/last_response_spec.rb
index ada665d59c..1d29b9b73f 100644
--- a/spec/ruby/library/net/ftp/last_response_spec.rb
+++ b/spec/ruby/library/net/ftp/last_response_spec.rb
@@ -1,25 +1,28 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#last_response" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#last_response" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "returns the last response" do
-    @ftp.last_response.should == "220 Dummy FTP Server ready!\n"
-    @ftp.help
-    @ftp.last_response.should == "211 System status, or system help reply. (HELP)\n"
+    it "returns the last response" do
+      @ftp.last_response.should == "220 Dummy FTP Server ready!\n"
+      @ftp.help
+      @ftp.last_response.should == "211 System status, or system help reply. (HELP)\n"
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/lastresp_spec.rb b/spec/ruby/library/net/ftp/lastresp_spec.rb
index 273e216e8b..9d26efb8f8 100644
--- a/spec/ruby/library/net/ftp/lastresp_spec.rb
+++ b/spec/ruby/library/net/ftp/lastresp_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'shared/last_response_code'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#lastresp" do
-  it_behaves_like :net_ftp_last_response_code, :lastresp
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'shared/last_response_code'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#lastresp" do
+    it_behaves_like :net_ftp_last_response_code, :lastresp
+  end
 end
diff --git a/spec/ruby/library/net/ftp/list_spec.rb b/spec/ruby/library/net/ftp/list_spec.rb
index 6175172923..6cffafeb4f 100644
--- a/spec/ruby/library/net/ftp/list_spec.rb
+++ b/spec/ruby/library/net/ftp/list_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/list'
 
-describe "Net::FTP#list" do
-  it_behaves_like :net_ftp_list, :list
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/list'
+
+  describe "Net::FTP#list" do
+    it_behaves_like :net_ftp_list, :list
+  end
 end
diff --git a/spec/ruby/library/net/ftp/login_spec.rb b/spec/ruby/library/net/ftp/login_spec.rb
index 46736851ee..981b439082 100644
--- a/spec/ruby/library/net/ftp/login_spec.rb
+++ b/spec/ruby/library/net/ftp/login_spec.rb
@@ -1,195 +1,198 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#login" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  describe "when passed no arguments" do
-    it "sends the USER command with 'anonymous' as name to the server" do
-      @ftp.login
-      @server.login_user.should == "anonymous"
-    end
-
-    it "sends 'anonymous@' as a password when required" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @ftp.login
-      @server.login_pass.should == "anonymous@"
-    end
-
-    it "raises a Net::FTPReplyError when the server requests an account" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @server.should_receive(:pass).and_respond("332 Need account for login.")
-      -> { @ftp.login }.should raise_error(Net::FTPReplyError)
-    end
-  end
-
-  describe "when passed name" do
-    it "sends the USER command with the passed name to the server" do
-      @ftp.login("rubyspec")
-      @server.login_user.should == "rubyspec"
-    end
-
-    it "raises a Net::FTPReplyError when the server requests a password, but none was given" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      -> { @ftp.login("rubyspec") }.should raise_error(Net::FTPReplyError)
-    end
-
-    it "raises a Net::FTPReplyError when the server requests an account, but none was given" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @server.should_receive(:pass).and_respond("332 Need account for login.")
-      -> { @ftp.login("rubyspec") }.should raise_error(Net::FTPReplyError)
-    end
-  end
-
-  describe "when passed name, password" do
-    it "sends the USER command with the passed name to the server" do
-      @ftp.login("rubyspec", "rocks")
-      @server.login_user.should == "rubyspec"
-    end
-
-    it "sends the passed password when required" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @ftp.login("rubyspec", "rocks")
-      @server.login_pass.should == "rocks"
-    end
-
-    it "raises a Net::FTPReplyError when the server requests an account" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @server.should_receive(:pass).and_respond("332 Need account for login.")
-      -> { @ftp.login("rubyspec", "rocks") }.should raise_error(Net::FTPReplyError)
-    end
-  end
-
-  describe "when passed name, password, account" do
-    it "sends the USER command with the passed name to the server" do
-      @ftp.login("rubyspec", "rocks", "account")
-      @server.login_user.should == "rubyspec"
-    end
-
-    it "sends the passed password when required" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @ftp.login("rubyspec", "rocks", "account")
-      @server.login_pass.should == "rocks"
-    end
-
-    it "sends the passed account when required" do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @server.should_receive(:pass).and_respond("332 Need account for login.")
-      @ftp.login("rubyspec", "rocks", "account")
-      @server.login_acct.should == "account"
-    end
-  end
-
-  describe "when the USER command fails" do
-    it "raises a Net::FTPPermError when the response code is 500" do
-      @server.should_receive(:user).and_respond("500 Syntax error, command unrecognized.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:user).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:user).and_respond("502 Command not implemented.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:user).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPTempError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:user).and_respond("530 Not logged in.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-  end
-
-  describe "when the PASS command fails" do
+  describe "Net::FTP#login" do
     before :each do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-    end
-
-    it "does not raise an Error when the response code is 202" do
-      @server.should_receive(:pass).and_respond("202 Command not implemented, superfluous at this site.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should_not raise_error
-    end
-
-    it "raises a Net::FTPPermError when the response code is 500" do
-      @server.should_receive(:pass).and_respond("500 Syntax error, command unrecognized.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:pass).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:pass).and_respond("502 Command not implemented.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:pass).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPTempError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:pass).and_respond("530 Not logged in.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-  end
-
-  describe "when the ACCT command fails" do
-    before :each do
-      @server.should_receive(:user).and_respond("331 User name okay, need password.")
-      @server.should_receive(:pass).and_respond("332 Need account for login.")
-    end
-
-    it "does not raise an Error when the response code is 202" do
-      @server.should_receive(:acct).and_respond("202 Command not implemented, superfluous at this site.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should_not raise_error
-    end
-
-    it "raises a Net::FTPPermError when the response code is 500" do
-      @server.should_receive(:acct).and_respond("500 Syntax error, command unrecognized.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:acct).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:acct).and_respond("502 Command not implemented.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:acct).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPTempError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:acct).and_respond("530 Not logged in.")
-      -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    describe "when passed no arguments" do
+      it "sends the USER command with 'anonymous' as name to the server" do
+        @ftp.login
+        @server.login_user.should == "anonymous"
+      end
+
+      it "sends 'anonymous@' as a password when required" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @ftp.login
+        @server.login_pass.should == "anonymous@"
+      end
+
+      it "raises a Net::FTPReplyError when the server requests an account" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @server.should_receive(:pass).and_respond("332 Need account for login.")
+        -> { @ftp.login }.should raise_error(Net::FTPReplyError)
+      end
+    end
+
+    describe "when passed name" do
+      it "sends the USER command with the passed name to the server" do
+        @ftp.login("rubyspec")
+        @server.login_user.should == "rubyspec"
+      end
+
+      it "raises a Net::FTPReplyError when the server requests a password, but none was given" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        -> { @ftp.login("rubyspec") }.should raise_error(Net::FTPReplyError)
+      end
+
+      it "raises a Net::FTPReplyError when the server requests an account, but none was given" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @server.should_receive(:pass).and_respond("332 Need account for login.")
+        -> { @ftp.login("rubyspec") }.should raise_error(Net::FTPReplyError)
+      end
+    end
+
+    describe "when passed name, password" do
+      it "sends the USER command with the passed name to the server" do
+        @ftp.login("rubyspec", "rocks")
+        @server.login_user.should == "rubyspec"
+      end
+
+      it "sends the passed password when required" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @ftp.login("rubyspec", "rocks")
+        @server.login_pass.should == "rocks"
+      end
+
+      it "raises a Net::FTPReplyError when the server requests an account" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @server.should_receive(:pass).and_respond("332 Need account for login.")
+        -> { @ftp.login("rubyspec", "rocks") }.should raise_error(Net::FTPReplyError)
+      end
+    end
+
+    describe "when passed name, password, account" do
+      it "sends the USER command with the passed name to the server" do
+        @ftp.login("rubyspec", "rocks", "account")
+        @server.login_user.should == "rubyspec"
+      end
+
+      it "sends the passed password when required" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @ftp.login("rubyspec", "rocks", "account")
+        @server.login_pass.should == "rocks"
+      end
+
+      it "sends the passed account when required" do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @server.should_receive(:pass).and_respond("332 Need account for login.")
+        @ftp.login("rubyspec", "rocks", "account")
+        @server.login_acct.should == "account"
+      end
+    end
+
+    describe "when the USER command fails" do
+      it "raises a Net::FTPPermError when the response code is 500" do
+        @server.should_receive(:user).and_respond("500 Syntax error, command unrecognized.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:user).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:user).and_respond("502 Command not implemented.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:user).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:user).and_respond("530 Not logged in.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+    end
+
+    describe "when the PASS command fails" do
+      before :each do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+      end
+
+      it "does not raise an Error when the response code is 202" do
+        @server.should_receive(:pass).and_respond("202 Command not implemented, superfluous at this site.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should_not raise_error
+      end
+
+      it "raises a Net::FTPPermError when the response code is 500" do
+        @server.should_receive(:pass).and_respond("500 Syntax error, command unrecognized.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:pass).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:pass).and_respond("502 Command not implemented.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:pass).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:pass).and_respond("530 Not logged in.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+    end
+
+    describe "when the ACCT command fails" do
+      before :each do
+        @server.should_receive(:user).and_respond("331 User name okay, need password.")
+        @server.should_receive(:pass).and_respond("332 Need account for login.")
+      end
+
+      it "does not raise an Error when the response code is 202" do
+        @server.should_receive(:acct).and_respond("202 Command not implemented, superfluous at this site.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should_not raise_error
+      end
+
+      it "raises a Net::FTPPermError when the response code is 500" do
+        @server.should_receive(:acct).and_respond("500 Syntax error, command unrecognized.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:acct).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:acct).and_respond("502 Command not implemented.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:acct).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:acct).and_respond("530 Not logged in.")
+        -> { @ftp.login("rubyspec", "rocks", "account") }.should raise_error(Net::FTPPermError)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/net/ftp/ls_spec.rb b/spec/ruby/library/net/ftp/ls_spec.rb
index e729eb9481..f262515865 100644
--- a/spec/ruby/library/net/ftp/ls_spec.rb
+++ b/spec/ruby/library/net/ftp/ls_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/list'
 
-describe "Net::FTP#ls" do
-  it_behaves_like :net_ftp_list, :ls
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/list'
+
+  describe "Net::FTP#ls" do
+    it_behaves_like :net_ftp_list, :ls
+  end
 end
diff --git a/spec/ruby/library/net/ftp/mdtm_spec.rb b/spec/ruby/library/net/ftp/mdtm_spec.rb
index b74cf8d3c7..ea55533c43 100644
--- a/spec/ruby/library/net/ftp/mdtm_spec.rb
+++ b/spec/ruby/library/net/ftp/mdtm_spec.rb
@@ -1,38 +1,41 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#mdtm" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#mdtm" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the MDTM with the passed filename command to the server" do
-    @ftp.mdtm("test.file")
-    @ftp.last_response.should == "213 19980705132316\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "returns the last modification time of the passed file" do
-    @ftp.mdtm("test.file").should == "19980705132316"
-  end
+    it "sends the MDTM with the passed filename command to the server" do
+      @ftp.mdtm("test.file")
+      @ftp.last_response.should == "213 19980705132316\n"
+    end
 
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:mdtm).and_respond("550 Requested action not taken.")
-    -> { @ftp.mdtm("test.file") }.should raise_error(Net::FTPPermError)
-  end
+    it "returns the last modification time of the passed file" do
+      @ftp.mdtm("test.file").should == "19980705132316"
+    end
+
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:mdtm).and_respond("550 Requested action not taken.")
+      -> { @ftp.mdtm("test.file") }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:mdtm).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.mdtm("test.file") }.should raise_error(Net::FTPTempError)
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:mdtm).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.mdtm("test.file") }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/mkdir_spec.rb b/spec/ruby/library/net/ftp/mkdir_spec.rb
index 7dc45b5711..2cb437a076 100644
--- a/spec/ruby/library/net/ftp/mkdir_spec.rb
+++ b/spec/ruby/library/net/ftp/mkdir_spec.rb
@@ -1,61 +1,64 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#mkdir" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#mkdir" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the MKD command with the passed pathname to the server" do
-    @ftp.mkdir("test.folder")
-    @ftp.last_response.should == %{257 "test.folder" created.\n}
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "returns the path to the newly created directory" do
-    @ftp.mkdir("test.folder").should == "test.folder"
-    @ftp.mkdir("/absolute/path/to/test.folder").should == "/absolute/path/to/test.folder"
-    @ftp.mkdir("relative/path/to/test.folder").should == "relative/path/to/test.folder"
-    @ftp.mkdir('/usr/dm/foo"bar').should == '/usr/dm/foo"bar'
-  end
+    it "sends the MKD command with the passed pathname to the server" do
+      @ftp.mkdir("test.folder")
+      @ftp.last_response.should == %{257 "test.folder" created.\n}
+    end
 
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:mkd).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
+    it "returns the path to the newly created directory" do
+      @ftp.mkdir("test.folder").should == "test.folder"
+      @ftp.mkdir("/absolute/path/to/test.folder").should == "/absolute/path/to/test.folder"
+      @ftp.mkdir("relative/path/to/test.folder").should == "relative/path/to/test.folder"
+      @ftp.mkdir('/usr/dm/foo"bar').should == '/usr/dm/foo"bar'
+    end
 
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:mkd).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:mkd).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:mkd).and_respond("502 Command not implemented.")
-    -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:mkd).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:mkd).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPTempError)
-  end
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:mkd).and_respond("502 Command not implemented.")
+      -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:mkd).and_respond("530 Not logged in.")
-    -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:mkd).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 530" do
+      @server.should_receive(:mkd).and_respond("530 Not logged in.")
+      -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:mkd).and_respond("550 Requested action not taken.")
-    -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:mkd).and_respond("550 Requested action not taken.")
+      -> { @ftp.mkdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/mtime_spec.rb b/spec/ruby/library/net/ftp/mtime_spec.rb
index 0f6cc1ba20..7265667a52 100644
--- a/spec/ruby/library/net/ftp/mtime_spec.rb
+++ b/spec/ruby/library/net/ftp/mtime_spec.rb
@@ -1,50 +1,53 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#mtime" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#mtime" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the MDTM with the passed filename command to the server" do
-    @ftp.mtime("test.file")
-    @ftp.last_response.should == "213 19980705132316\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  describe "when passed filename" do
-    it "returns the last modification time of the passed file as a Time object in the local time" do
-      @ftp.mtime("test.file").should == Time.gm("1998", "07", "05", "13", "23", "16")
+    it "sends the MDTM with the passed filename command to the server" do
+      @ftp.mtime("test.file")
+      @ftp.last_response.should == "213 19980705132316\n"
     end
-  end
 
-  describe "when passed filename, local_time" do
-    it "returns the last modification time as a Time object in UTC when local_time is true" do
-      @ftp.mtime("test.file", true).should == Time.local("1998", "07", "05", "13", "23", "16")
+    describe "when passed filename" do
+      it "returns the last modification time of the passed file as a Time object in the local time" do
+        @ftp.mtime("test.file").should == Time.gm("1998", "07", "05", "13", "23", "16")
+      end
     end
 
-    it "returns the last modification time as a Time object in the local time when local_time is false" do
-      @ftp.mtime("test.file", false).should == Time.gm("1998", "07", "05", "13", "23", "16")
+    describe "when passed filename, local_time" do
+      it "returns the last modification time as a Time object in UTC when local_time is true" do
+        @ftp.mtime("test.file", true).should == Time.local("1998", "07", "05", "13", "23", "16")
+      end
+
+      it "returns the last modification time as a Time object in the local time when local_time is false" do
+        @ftp.mtime("test.file", false).should == Time.gm("1998", "07", "05", "13", "23", "16")
+      end
     end
-  end
 
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:mdtm).and_respond("550 Requested action not taken.")
-    -> { @ftp.mtime("test.file") }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:mdtm).and_respond("550 Requested action not taken.")
+      -> { @ftp.mtime("test.file") }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:mdtm).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.mtime("test.file") }.should raise_error(Net::FTPTempError)
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:mdtm).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.mtime("test.file") }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/nlst_spec.rb b/spec/ruby/library/net/ftp/nlst_spec.rb
index 34384fb8c4..0de84b3a76 100644
--- a/spec/ruby/library/net/ftp/nlst_spec.rb
+++ b/spec/ruby/library/net/ftp/nlst_spec.rb
@@ -1,92 +1,95 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#nlst" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.passive = false
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+  describe "Net::FTP#nlst" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  describe "when passed no arguments" do
-    it "returns an Array containing a list of files in the current dir" do
-      @ftp.nlst.should == ["last_response_code.rb", "list.rb", "pwd.rb"]
-      @ftp.last_response.should == "226 transfer complete (NLST)\n"
+      @ftp = Net::FTP.new
+      @ftp.passive = false
+      @ftp.connect(@server.hostname, @server.server_port)
     end
-  end
 
-  describe "when passed dir" do
-    it "returns an Array containing a list of files in the passed dir" do
-      @ftp.nlst("test.folder").should == ["last_response_code.rb", "list.rb", "pwd.rb"]
-      @ftp.last_response.should == "226 transfer complete (NLST test.folder)\n"
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
     end
-  end
 
-  describe "when the NLST command fails" do
-    it "raises a Net::FTPTempError when the response code is 450" do
-      @server.should_receive(:nlst).and_respond("450 Requested file action not taken..")
-      -> { @ftp.nlst }.should raise_error(Net::FTPTempError)
+    describe "when passed no arguments" do
+      it "returns an Array containing a list of files in the current dir" do
+        @ftp.nlst.should == ["last_response_code.rb", "list.rb", "pwd.rb"]
+        @ftp.last_response.should == "226 transfer complete (NLST)\n"
+      end
     end
 
-    it "raises a Net::FTPPermError when the response code is 500" do
-      @server.should_receive(:nlst).and_respond("500 Syntax error, command unrecognized.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+    describe "when passed dir" do
+      it "returns an Array containing a list of files in the passed dir" do
+        @ftp.nlst("test.folder").should == ["last_response_code.rb", "list.rb", "pwd.rb"]
+        @ftp.last_response.should == "226 transfer complete (NLST test.folder)\n"
+      end
     end
 
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:nlst).and_respond("501 Syntax error, command unrecognized.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
-    end
+    describe "when the NLST command fails" do
+      it "raises a Net::FTPTempError when the response code is 450" do
+        @server.should_receive(:nlst).and_respond("450 Requested file action not taken..")
+        -> { @ftp.nlst }.should raise_error(Net::FTPTempError)
+      end
 
-    it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:nlst).and_respond("502 Command not implemented.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
-    end
+      it "raises a Net::FTPPermError when the response code is 500" do
+        @server.should_receive(:nlst).and_respond("500 Syntax error, command unrecognized.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
 
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:nlst).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPTempError)
-    end
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:nlst).and_respond("501 Syntax error, command unrecognized.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
 
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:nlst).and_respond("530 Not logged in.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
-    end
-  end
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:nlst).and_respond("502 Command not implemented.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
 
-  describe "when opening the data port fails" do
-    it "raises a Net::FTPPermError when the response code is 500" do
-      @server.should_receive(:eprt).and_respond("500 Syntax error, command unrecognized.")
-      @server.should_receive(:port).and_respond("500 Syntax error, command unrecognized.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
-    end
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:nlst).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPTempError)
+      end
 
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:eprt).and_respond("501 Syntax error in parameters or arguments.")
-      @server.should_receive(:port).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:nlst).and_respond("530 Not logged in.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
     end
 
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:eprt).and_respond("421 Service not available, closing control connection.")
-      @server.should_receive(:port).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPTempError)
-    end
+    describe "when opening the data port fails" do
+      it "raises a Net::FTPPermError when the response code is 500" do
+        @server.should_receive(:eprt).and_respond("500 Syntax error, command unrecognized.")
+        @server.should_receive(:port).and_respond("500 Syntax error, command unrecognized.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:eprt).and_respond("501 Syntax error in parameters or arguments.")
+        @server.should_receive(:port).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:eprt).and_respond("421 Service not available, closing control connection.")
+        @server.should_receive(:port).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPTempError)
+      end
 
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:eprt).and_respond("530 Not logged in.")
-      @server.should_receive(:port).and_respond("530 Not logged in.")
-      -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:eprt).and_respond("530 Not logged in.")
+        @server.should_receive(:port).and_respond("530 Not logged in.")
+        -> { @ftp.nlst }.should raise_error(Net::FTPPermError)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/net/ftp/noop_spec.rb b/spec/ruby/library/net/ftp/noop_spec.rb
index 070750ced7..71011d4af7 100644
--- a/spec/ruby/library/net/ftp/noop_spec.rb
+++ b/spec/ruby/library/net/ftp/noop_spec.rb
@@ -1,38 +1,41 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#noop" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#noop" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the NOOP command to the server" do
-    @ftp.noop
-    @ftp.last_response.should == "200 Command okay. (NOOP)\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "returns nil" do
-    @ftp.noop.should be_nil
-  end
+    it "sends the NOOP command to the server" do
+      @ftp.noop
+      @ftp.last_response.should == "200 Command okay. (NOOP)\n"
+    end
 
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:noop).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.noop }.should raise_error(Net::FTPPermError)
-  end
+    it "returns nil" do
+      @ftp.noop.should be_nil
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:noop).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.noop }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:noop).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.noop }.should raise_error(Net::FTPTempError)
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:noop).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.noop }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/open_spec.rb b/spec/ruby/library/net/ftp/open_spec.rb
index 7be02ff373..89187b9802 100644
--- a/spec/ruby/library/net/ftp/open_spec.rb
+++ b/spec/ruby/library/net/ftp/open_spec.rb
@@ -1,55 +1,58 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP.open" do
-  before :each do
-    @ftp = mock("Net::FTP instance")
-    Net::FTP.stub!(:new).and_return(@ftp)
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-  describe "when passed no block" do
-    it "returns a new Net::FTP instance" do
-      Net::FTP.open("localhost").should equal(@ftp)
+  describe "Net::FTP.open" do
+    before :each do
+      @ftp = mock("Net::FTP instance")
+      Net::FTP.stub!(:new).and_return(@ftp)
     end
 
-    it "passes the passed arguments down to Net::FTP.new" do
-      Net::FTP.should_receive(:new).with("localhost", "user", "password", "account")
-      Net::FTP.open("localhost", "user", "password", "account")
-    end
-  end
+    describe "when passed no block" do
+      it "returns a new Net::FTP instance" do
+        Net::FTP.open("localhost").should equal(@ftp)
+      end
 
-  describe "when passed a block" do
-    before :each do
-      @ftp.stub!(:close)
+      it "passes the passed arguments down to Net::FTP.new" do
+        Net::FTP.should_receive(:new).with("localhost", "user", "password", "account")
+        Net::FTP.open("localhost", "user", "password", "account")
+      end
     end
 
-    it "yields a new Net::FTP instance to the passed block" do
-      yielded = false
-      Net::FTP.open("localhost") do |ftp|
-        yielded = true
-        ftp.should equal(@ftp)
+    describe "when passed a block" do
+      before :each do
+        @ftp.stub!(:close)
       end
-      yielded.should be_true
-    end
 
-    it "closes the Net::FTP instance after yielding" do
-      Net::FTP.open("localhost") do |ftp|
-        ftp.should_receive(:close)
+      it "yields a new Net::FTP instance to the passed block" do
+        yielded = false
+        Net::FTP.open("localhost") do |ftp|
+          yielded = true
+          ftp.should equal(@ftp)
+        end
+        yielded.should be_true
       end
-    end
 
-    it "closes the Net::FTP instance even if an exception is raised while yielding" do
-      begin
+      it "closes the Net::FTP instance after yielding" do
         Net::FTP.open("localhost") do |ftp|
           ftp.should_receive(:close)
-          raise ArgumentError, "some exception"
         end
-      rescue ArgumentError
       end
-    end
 
-    it "returns the block's return value" do
-      Net::FTP.open("localhost") { :test }.should == :test
+      it "closes the Net::FTP instance even if an exception is raised while yielding" do
+        begin
+          Net::FTP.open("localhost") do |ftp|
+            ftp.should_receive(:close)
+            raise ArgumentError, "some exception"
+          end
+        rescue ArgumentError
+        end
+      end
+
+      it "returns the block's return value" do
+        Net::FTP.open("localhost") { :test }.should == :test
+      end
     end
   end
 end
diff --git a/spec/ruby/library/net/ftp/passive_spec.rb b/spec/ruby/library/net/ftp/passive_spec.rb
index e8db030cbd..f9c34efb7d 100644
--- a/spec/ruby/library/net/ftp/passive_spec.rb
+++ b/spec/ruby/library/net/ftp/passive_spec.rb
@@ -1,28 +1,31 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#passive" do
-  it "returns true when self is in passive mode" do
-    ftp = Net::FTP.new
-    ftp.passive.should be_false
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-    ftp.passive = true
-    ftp.passive.should be_true
-  end
+  describe "Net::FTP#passive" do
+    it "returns true when self is in passive mode" do
+      ftp = Net::FTP.new
+      ftp.passive.should be_false
+
+      ftp.passive = true
+      ftp.passive.should be_true
+    end
 
-  it "is the value of Net::FTP.default_value by default" do
-    ruby_exe(fixture(__FILE__, "passive.rb")).should == "true"
+    it "is the value of Net::FTP.default_value by default" do
+      ruby_exe(fixture(__FILE__, "passive.rb")).should == "true"
+    end
   end
-end
 
-describe "Net::FTP#passive=" do
-  it "sets self to passive mode when passed true" do
-    ftp = Net::FTP.new
+  describe "Net::FTP#passive=" do
+    it "sets self to passive mode when passed true" do
+      ftp = Net::FTP.new
 
-    ftp.passive = true
-    ftp.passive.should be_true
+      ftp.passive = true
+      ftp.passive.should be_true
 
-    ftp.passive = false
-    ftp.passive.should be_false
+      ftp.passive = false
+      ftp.passive.should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/put_spec.rb b/spec/ruby/library/net/ftp/put_spec.rb
index f1f85b5d05..36ba6c1963 100644
--- a/spec/ruby/library/net/ftp/put_spec.rb
+++ b/spec/ruby/library/net/ftp/put_spec.rb
@@ -1,21 +1,24 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/puttextfile'
-require_relative 'shared/putbinaryfile'
 
-describe "Net::FTP#put (binary mode)" do
-  before :each do
-    @binary_mode = true
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/puttextfile'
+  require_relative 'shared/putbinaryfile'
 
-  it_behaves_like :net_ftp_putbinaryfile, :put
-end
+  describe "Net::FTP#put (binary mode)" do
+    before :each do
+      @binary_mode = true
+    end
 
-describe "Net::FTP#put (text mode)" do
-  before :each do
-    @binary_mode = false
+    it_behaves_like :net_ftp_putbinaryfile, :put
   end
 
-  it_behaves_like :net_ftp_puttextfile, :put
+  describe "Net::FTP#put (text mode)" do
+    before :each do
+      @binary_mode = false
+    end
+
+    it_behaves_like :net_ftp_puttextfile, :put
+  end
 end
diff --git a/spec/ruby/library/net/ftp/putbinaryfile_spec.rb b/spec/ruby/library/net/ftp/putbinaryfile_spec.rb
index cb1c7bef5a..6ced5246fe 100644
--- a/spec/ruby/library/net/ftp/putbinaryfile_spec.rb
+++ b/spec/ruby/library/net/ftp/putbinaryfile_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/putbinaryfile'
 
-describe "Net::FTP#putbinaryfile" do
-  it_behaves_like :net_ftp_putbinaryfile, :putbinaryfile
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/putbinaryfile'
+
+  describe "Net::FTP#putbinaryfile" do
+    it_behaves_like :net_ftp_putbinaryfile, :putbinaryfile
+  end
 end
diff --git a/spec/ruby/library/net/ftp/puttextfile_spec.rb b/spec/ruby/library/net/ftp/puttextfile_spec.rb
index 00a930afd7..0cab6bd3c3 100644
--- a/spec/ruby/library/net/ftp/puttextfile_spec.rb
+++ b/spec/ruby/library/net/ftp/puttextfile_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
-require_relative 'shared/puttextfile'
 
-describe "Net::FTP#puttextfile" do
-  it_behaves_like :net_ftp_puttextfile, :puttextfile
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+  require_relative 'shared/puttextfile'
+
+  describe "Net::FTP#puttextfile" do
+    it_behaves_like :net_ftp_puttextfile, :puttextfile
+  end
 end
diff --git a/spec/ruby/library/net/ftp/pwd_spec.rb b/spec/ruby/library/net/ftp/pwd_spec.rb
index a3998cc730..856ff5ff9b 100644
--- a/spec/ruby/library/net/ftp/pwd_spec.rb
+++ b/spec/ruby/library/net/ftp/pwd_spec.rb
@@ -1,53 +1,56 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#pwd" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the PWD command to the server" do
-    @ftp.pwd
-    @ftp.last_response.should == "257 \"/some/dir/\" - current directory\n"
-  end
-
-  it "returns the current directory" do
-    @ftp.pwd.should == "/some/dir/"
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:pwd).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:pwd).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:pwd).and_respond("502 Command not implemented.")
-    -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:pwd).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.pwd }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:pwd).and_respond("550 Requested action not taken.")
-    -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#pwd" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the PWD command to the server" do
+      @ftp.pwd
+      @ftp.last_response.should == "257 \"/some/dir/\" - current directory\n"
+    end
+
+    it "returns the current directory" do
+      @ftp.pwd.should == "/some/dir/"
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:pwd).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:pwd).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:pwd).and_respond("502 Command not implemented.")
+      -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:pwd).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.pwd }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:pwd).and_respond("550 Requested action not taken.")
+      -> { @ftp.pwd }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/quit_spec.rb b/spec/ruby/library/net/ftp/quit_spec.rb
index 8e3cb28b90..12b9fd3cee 100644
--- a/spec/ruby/library/net/ftp/quit_spec.rb
+++ b/spec/ruby/library/net/ftp/quit_spec.rb
@@ -1,33 +1,36 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#quit" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#quit" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the QUIT command to the server" do
-    @ftp.quit
-    @ftp.last_response.should == "221 OK, bye\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "does not close the socket automatically" do
-    @ftp.quit
-    @ftp.closed?.should be_false
-  end
+    it "sends the QUIT command to the server" do
+      @ftp.quit
+      @ftp.last_response.should == "221 OK, bye\n"
+    end
+
+    it "does not close the socket automatically" do
+      @ftp.quit
+      @ftp.closed?.should be_false
+    end
 
-  it "returns nil" do
-    @ftp.quit.should be_nil
+    it "returns nil" do
+      @ftp.quit.should be_nil
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/rename_spec.rb b/spec/ruby/library/net/ftp/rename_spec.rb
index 376b203ac9..aa7c1360b5 100644
--- a/spec/ruby/library/net/ftp/rename_spec.rb
+++ b/spec/ruby/library/net/ftp/rename_spec.rb
@@ -1,94 +1,97 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#rename" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  describe "when passed from_name, to_name" do
-    it "sends the RNFR command with the passed from_name and the RNTO command with the passed to_name to the server" do
-      @ftp.rename("from.file", "to.file")
-      @ftp.last_response.should == "250 Requested file action okay, completed. (Renamed from.file to to.file)\n"
-    end
-
-    it "returns something" do
-      @ftp.rename("from.file", "to.file").should be_nil
-    end
-  end
-
-  describe "when the RNFR command fails" do
-    it "raises a Net::FTPTempError when the response code is 450" do
-      @server.should_receive(:rnfr).and_respond("450 Requested file action not taken.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPTempError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 550" do
-      @server.should_receive(:rnfr).and_respond("550 Requested action not taken.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:rnfr).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
-    end
+  describe "Net::FTP#rename" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-    it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:rnfr).and_respond("502 Command not implemented.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
     end
 
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:rnfr).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPTempError)
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
     end
 
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:rnfr).and_respond("530 Not logged in.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
-    end
-  end
-
-  describe "when the RNTO command fails" do
-    it "raises a Net::FTPPermError when the response code is 532" do
-      @server.should_receive(:rnfr).and_respond("532 Need account for storing files.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 553" do
-      @server.should_receive(:rnto).and_respond("553 Requested action not taken.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
-    end
-
-    it "raises a Net::FTPPermError when the response code is 501" do
-      @server.should_receive(:rnto).and_respond("501 Syntax error in parameters or arguments.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
-    end
+    describe "when passed from_name, to_name" do
+      it "sends the RNFR command with the passed from_name and the RNTO command with the passed to_name to the server" do
+        @ftp.rename("from.file", "to.file")
+        @ftp.last_response.should == "250 Requested file action okay, completed. (Renamed from.file to to.file)\n"
+      end
 
-    it "raises a Net::FTPPermError when the response code is 502" do
-      @server.should_receive(:rnto).and_respond("502 Command not implemented.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      it "returns something" do
+        @ftp.rename("from.file", "to.file").should be_nil
+      end
     end
 
-    it "raises a Net::FTPTempError when the response code is 421" do
-      @server.should_receive(:rnto).and_respond("421 Service not available, closing control connection.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPTempError)
+    describe "when the RNFR command fails" do
+      it "raises a Net::FTPTempError when the response code is 450" do
+        @server.should_receive(:rnfr).and_respond("450 Requested file action not taken.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 550" do
+        @server.should_receive(:rnfr).and_respond("550 Requested action not taken.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:rnfr).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:rnfr).and_respond("502 Command not implemented.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:rnfr).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:rnfr).and_respond("530 Not logged in.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
     end
 
-    it "raises a Net::FTPPermError when the response code is 530" do
-      @server.should_receive(:rnto).and_respond("530 Not logged in.")
-      -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+    describe "when the RNTO command fails" do
+      it "raises a Net::FTPPermError when the response code is 532" do
+        @server.should_receive(:rnfr).and_respond("532 Need account for storing files.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 553" do
+        @server.should_receive(:rnto).and_respond("553 Requested action not taken.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 501" do
+        @server.should_receive(:rnto).and_respond("501 Syntax error in parameters or arguments.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 502" do
+        @server.should_receive(:rnto).and_respond("502 Command not implemented.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
+
+      it "raises a Net::FTPTempError when the response code is 421" do
+        @server.should_receive(:rnto).and_respond("421 Service not available, closing control connection.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPTempError)
+      end
+
+      it "raises a Net::FTPPermError when the response code is 530" do
+        @server.should_receive(:rnto).and_respond("530 Not logged in.")
+        -> { @ftp.rename("from.file", "to.file") }.should raise_error(Net::FTPPermError)
+      end
     end
   end
 end
diff --git a/spec/ruby/library/net/ftp/resume_spec.rb b/spec/ruby/library/net/ftp/resume_spec.rb
index 51b1cff2a4..1b575c29f1 100644
--- a/spec/ruby/library/net/ftp/resume_spec.rb
+++ b/spec/ruby/library/net/ftp/resume_spec.rb
@@ -1,23 +1,26 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#resume" do
-  it "returns true when self is set to resume uploads/downloads" do
-    ftp = Net::FTP.new
-    ftp.resume.should be_false
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-    ftp.resume = true
-    ftp.resume.should be_true
+  describe "Net::FTP#resume" do
+    it "returns true when self is set to resume uploads/downloads" do
+      ftp = Net::FTP.new
+      ftp.resume.should be_false
+
+      ftp.resume = true
+      ftp.resume.should be_true
+    end
   end
-end
 
-describe "Net::FTP#resume=" do
-  it "sets self to resume uploads/downloads when set to true" do
-    ftp = Net::FTP.new
-    ftp.resume = true
-    ftp.resume.should be_true
+  describe "Net::FTP#resume=" do
+    it "sets self to resume uploads/downloads when set to true" do
+      ftp = Net::FTP.new
+      ftp.resume = true
+      ftp.resume.should be_true
 
-    ftp.resume = false
-    ftp.resume.should be_false
+      ftp.resume = false
+      ftp.resume.should be_false
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/retrbinary_spec.rb b/spec/ruby/library/net/ftp/retrbinary_spec.rb
index 30e2484af5..1f89f0d454 100644
--- a/spec/ruby/library/net/ftp/retrbinary_spec.rb
+++ b/spec/ruby/library/net/ftp/retrbinary_spec.rb
@@ -1,30 +1,33 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#retrbinary" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#retrbinary" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the passed command to the server" do
-    @ftp.retrbinary("RETR test", 4096) {}
-    @ftp.last_response.should == "226 Closing data connection. (RETR test)\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the passed command to the server" do
+      @ftp.retrbinary("RETR test", 4096) {}
+      @ftp.last_response.should == "226 Closing data connection. (RETR test)\n"
+    end
 
-  it "yields the received content as binary blocks of the passed size" do
-    res = []
-    @ftp.retrbinary("RETR test", 10) { |bin| res << bin }
-    res.should == [ "This is th", "e content\n", "of the fil", "e named 't", "est'.\n" ]
+    it "yields the received content as binary blocks of the passed size" do
+      res = []
+      @ftp.retrbinary("RETR test", 10) { |bin| res << bin }
+      res.should == [ "This is th", "e content\n", "of the fil", "e named 't", "est'.\n" ]
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/retrlines_spec.rb b/spec/ruby/library/net/ftp/retrlines_spec.rb
index 546df3844e..f26b008680 100644
--- a/spec/ruby/library/net/ftp/retrlines_spec.rb
+++ b/spec/ruby/library/net/ftp/retrlines_spec.rb
@@ -1,34 +1,37 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#retrlines" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#retrlines" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the passed command over the socket" do
-    @ftp.retrlines("LIST test.dir") {}
-    @ftp.last_response.should == "226 transfer complete (LIST test.dir)\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the passed command over the socket" do
+      @ftp.retrlines("LIST test.dir") {}
+      @ftp.last_response.should == "226 transfer complete (LIST test.dir)\n"
+    end
 
-  it "yields each received line to the passed block" do
-    res = []
-    @ftp.retrlines("LIST test.dir") { |x| res << x }
-    res.should == [
-      "-rw-r--r--  1 spec  staff  507 17 Jul 18:41 last_response_code.rb",
-      "-rw-r--r--  1 spec  staff   50 17 Jul 18:41 list.rb",
-      "-rw-r--r--  1 spec  staff   48 17 Jul 18:41 pwd.rb"
-    ]
+    it "yields each received line to the passed block" do
+      res = []
+      @ftp.retrlines("LIST test.dir") { |x| res << x }
+      res.should == [
+        "-rw-r--r--  1 spec  staff  507 17 Jul 18:41 last_response_code.rb",
+        "-rw-r--r--  1 spec  staff   50 17 Jul 18:41 list.rb",
+        "-rw-r--r--  1 spec  staff   48 17 Jul 18:41 pwd.rb"
+      ]
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/return_code_spec.rb b/spec/ruby/library/net/ftp/return_code_spec.rb
index e4b98c8031..67fc9d3b19 100644
--- a/spec/ruby/library/net/ftp/return_code_spec.rb
+++ b/spec/ruby/library/net/ftp/return_code_spec.rb
@@ -1,24 +1,27 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#return_code" do
-  before :each do
-    @ftp = Net::FTP.new
-  end
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
 
-  it "outputs a warning and returns a newline" do
-    -> do
-      @ftp.return_code.should == "\n"
-    end.should complain(/warning: Net::FTP#return_code is obsolete and do nothing/)
-  end
-end
+  describe "Net::FTP#return_code" do
+    before :each do
+      @ftp = Net::FTP.new
+    end
 
-describe "Net::FTP#return_code=" do
-  before :each do
-    @ftp = Net::FTP.new
+    it "outputs a warning and returns a newline" do
+      -> do
+        @ftp.return_code.should == "\n"
+      end.should complain(/warning: Net::FTP#return_code is obsolete and do nothing/)
+    end
   end
 
-  it "outputs a warning" do
-    -> { @ftp.return_code = 123 }.should complain(/warning: Net::FTP#return_code= is obsolete and do nothing/)
+  describe "Net::FTP#return_code=" do
+    before :each do
+      @ftp = Net::FTP.new
+    end
+
+    it "outputs a warning" do
+      -> { @ftp.return_code = 123 }.should complain(/warning: Net::FTP#return_code= is obsolete and do nothing/)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/rmdir_spec.rb b/spec/ruby/library/net/ftp/rmdir_spec.rb
index 0515897998..5b9586c6f0 100644
--- a/spec/ruby/library/net/ftp/rmdir_spec.rb
+++ b/spec/ruby/library/net/ftp/rmdir_spec.rb
@@ -1,58 +1,61 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#rmdir" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the RMD command with the passed pathname to the server" do
-    @ftp.rmdir("test.folder")
-    @ftp.last_response.should == "250 Requested file action okay, completed. (RMD test.folder)\n"
-  end
-
-  it "returns nil" do
-    @ftp.rmdir("test.folder").should be_nil
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:rmd).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:rmd).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:rmd).and_respond("502 Command not implemented.")
-    -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:rmd).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:rmd).and_respond("530 Not logged in.")
-    -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:rmd).and_respond("550 Requested action not taken.")
-    -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#rmdir" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the RMD command with the passed pathname to the server" do
+      @ftp.rmdir("test.folder")
+      @ftp.last_response.should == "250 Requested file action okay, completed. (RMD test.folder)\n"
+    end
+
+    it "returns nil" do
+      @ftp.rmdir("test.folder").should be_nil
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:rmd).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:rmd).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:rmd).and_respond("502 Command not implemented.")
+      -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:rmd).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 530" do
+      @server.should_receive(:rmd).and_respond("530 Not logged in.")
+      -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:rmd).and_respond("550 Requested action not taken.")
+      -> { @ftp.rmdir("test.folder") }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/sendcmd_spec.rb b/spec/ruby/library/net/ftp/sendcmd_spec.rb
index dafa36e032..fefb89ae0b 100644
--- a/spec/ruby/library/net/ftp/sendcmd_spec.rb
+++ b/spec/ruby/library/net/ftp/sendcmd_spec.rb
@@ -1,54 +1,57 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#sendcmd" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the passed command to the server" do
-    @ftp.sendcmd("HELP")
-    @ftp.last_response.should == "211 System status, or system help reply. (HELP)\n"
-  end
-
-  it "returns the server's response" do
-    @ftp.sendcmd("HELP").should == "211 System status, or system help reply. (HELP)\n"
-  end
-
-  it "raises no error when the response code is 1xx, 2xx or 3xx" do
-    @server.should_receive(:help).and_respond("120 Service ready in nnn minutes.")
-    -> { @ftp.sendcmd("HELP") }.should_not raise_error
-
-    @server.should_receive(:help).and_respond("200 Command okay.")
-    -> { @ftp.sendcmd("HELP") }.should_not raise_error
-
-    @server.should_receive(:help).and_respond("350 Requested file action pending further information.")
-    -> { @ftp.sendcmd("HELP") }.should_not raise_error
-  end
-
-  it "raises a Net::FTPTempError when the response code is 4xx" do
-    @server.should_receive(:help).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.sendcmd("HELP") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 5xx" do
-    @server.should_receive(:help).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.sendcmd("HELP") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPProtoError when the response code is not between 1xx-5xx" do
-    @server.should_receive(:help).and_respond("999 Invalid response.")
-    -> { @ftp.sendcmd("HELP") }.should raise_error(Net::FTPProtoError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#sendcmd" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the passed command to the server" do
+      @ftp.sendcmd("HELP")
+      @ftp.last_response.should == "211 System status, or system help reply. (HELP)\n"
+    end
+
+    it "returns the server's response" do
+      @ftp.sendcmd("HELP").should == "211 System status, or system help reply. (HELP)\n"
+    end
+
+    it "raises no error when the response code is 1xx, 2xx or 3xx" do
+      @server.should_receive(:help).and_respond("120 Service ready in nnn minutes.")
+      -> { @ftp.sendcmd("HELP") }.should_not raise_error
+
+      @server.should_receive(:help).and_respond("200 Command okay.")
+      -> { @ftp.sendcmd("HELP") }.should_not raise_error
+
+      @server.should_receive(:help).and_respond("350 Requested file action pending further information.")
+      -> { @ftp.sendcmd("HELP") }.should_not raise_error
+    end
+
+    it "raises a Net::FTPTempError when the response code is 4xx" do
+      @server.should_receive(:help).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.sendcmd("HELP") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 5xx" do
+      @server.should_receive(:help).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.sendcmd("HELP") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPProtoError when the response code is not between 1xx-5xx" do
+      @server.should_receive(:help).and_respond("999 Invalid response.")
+      -> { @ftp.sendcmd("HELP") }.should raise_error(Net::FTPProtoError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/set_socket_spec.rb b/spec/ruby/library/net/ftp/set_socket_spec.rb
index 7ca3bbbe27..6c8b58fb79 100644
--- a/spec/ruby/library/net/ftp/set_socket_spec.rb
+++ b/spec/ruby/library/net/ftp/set_socket_spec.rb
@@ -1,8 +1,11 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
 
-describe "Net::FTP#set_socket" do
-  # TODO: I won't spec this method, as it is not used
-  #       anywhere and it should be private anyway.
-  it "needs to be reviewed for spec completeness"
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+
+  describe "Net::FTP#set_socket" do
+    # TODO: I won't spec this method, as it is not used
+    #       anywhere and it should be private anyway.
+    it "needs to be reviewed for spec completeness"
+  end
 end
diff --git a/spec/ruby/library/net/ftp/site_spec.rb b/spec/ruby/library/net/ftp/site_spec.rb
index 4d6a9b4a0c..ca4f499112 100644
--- a/spec/ruby/library/net/ftp/site_spec.rb
+++ b/spec/ruby/library/net/ftp/site_spec.rb
@@ -1,53 +1,56 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#site" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the SITE command with the passed argument to the server" do
-    @ftp.site("param")
-    @ftp.last_response.should == "200 Command okay. (SITE param)\n"
-  end
-
-  it "returns nil" do
-    @ftp.site("param").should be_nil
-  end
-
-  it "does not raise an error when the response code is 202" do
-    @server.should_receive(:site).and_respond("202 Command not implemented, superfluous at this site.")
-    -> { @ftp.site("param") }.should_not raise_error
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:site).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.site("param") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:site).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.site("param") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:site).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.site("param") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:site).and_respond("530 Requested action not taken.")
-    -> { @ftp.site("param") }.should raise_error(Net::FTPPermError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#site" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the SITE command with the passed argument to the server" do
+      @ftp.site("param")
+      @ftp.last_response.should == "200 Command okay. (SITE param)\n"
+    end
+
+    it "returns nil" do
+      @ftp.site("param").should be_nil
+    end
+
+    it "does not raise an error when the response code is 202" do
+      @server.should_receive(:site).and_respond("202 Command not implemented, superfluous at this site.")
+      -> { @ftp.site("param") }.should_not raise_error
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:site).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.site("param") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:site).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.site("param") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:site).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.site("param") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 530" do
+      @server.should_receive(:site).and_respond("530 Requested action not taken.")
+      -> { @ftp.site("param") }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/size_spec.rb b/spec/ruby/library/net/ftp/size_spec.rb
index 17615079e9..0c20b10549 100644
--- a/spec/ruby/library/net/ftp/size_spec.rb
+++ b/spec/ruby/library/net/ftp/size_spec.rb
@@ -1,48 +1,51 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#size" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the SIZE command to the server" do
-    @ftp.size("test.file")
-    @ftp.last_response.should == "213 1024\n"
-  end
-
-  it "returns the size of the passed file as Integer" do
-    @ftp.size("test.file").should eql(1024)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:size).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.size("test.file") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:size).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.size("test.file") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:size).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.size("test.file") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 550" do
-    @server.should_receive(:size).and_respond("550 Requested action not taken.")
-    -> { @ftp.size("test.file") }.should raise_error(Net::FTPPermError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#size" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the SIZE command to the server" do
+      @ftp.size("test.file")
+      @ftp.last_response.should == "213 1024\n"
+    end
+
+    it "returns the size of the passed file as Integer" do
+      @ftp.size("test.file").should eql(1024)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:size).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.size("test.file") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:size).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.size("test.file") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:size).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.size("test.file") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 550" do
+      @server.should_receive(:size).and_respond("550 Requested action not taken.")
+      -> { @ftp.size("test.file") }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/status_spec.rb b/spec/ruby/library/net/ftp/status_spec.rb
index 6e3840bf93..03bc5d6e05 100644
--- a/spec/ruby/library/net/ftp/status_spec.rb
+++ b/spec/ruby/library/net/ftp/status_spec.rb
@@ -1,67 +1,70 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#status" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#status" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-  it "sends the STAT command to the server" do
-    @ftp.status
-    @ftp.last_response.should == "211 System status, or system help reply. (STAT)\n"
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "sends the STAT command with an optional parameter to the server" do
-    @ftp.status("/pub").should == "211 System status, or system help reply. (STAT /pub)\n"
-  end
+    it "sends the STAT command to the server" do
+      @ftp.status
+      @ftp.last_response.should == "211 System status, or system help reply. (STAT)\n"
+    end
 
-  it "returns the received information" do
-    @ftp.status.should == "211 System status, or system help reply. (STAT)\n"
-  end
+    it "sends the STAT command with an optional parameter to the server" do
+      @ftp.status("/pub").should == "211 System status, or system help reply. (STAT /pub)\n"
+    end
 
-  it "does not raise an error when the response code is 212" do
-    @server.should_receive(:stat).and_respond("212 Directory status.")
-    -> { @ftp.status }.should_not raise_error
-  end
+    it "returns the received information" do
+      @ftp.status.should == "211 System status, or system help reply. (STAT)\n"
+    end
 
-  it "does not raise an error when the response code is 213" do
-    @server.should_receive(:stat).and_respond("213 File status.")
-    -> { @ftp.status }.should_not raise_error
-  end
+    it "does not raise an error when the response code is 212" do
+      @server.should_receive(:stat).and_respond("212 Directory status.")
+      -> { @ftp.status }.should_not raise_error
+    end
 
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:stat).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.status }.should raise_error(Net::FTPPermError)
-  end
+    it "does not raise an error when the response code is 213" do
+      @server.should_receive(:stat).and_respond("213 File status.")
+      -> { @ftp.status }.should_not raise_error
+    end
 
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:stat).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.status }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:stat).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.status }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:stat).and_respond("502 Command not implemented.")
-    -> { @ftp.status }.should raise_error(Net::FTPPermError)
-  end
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:stat).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.status }.should raise_error(Net::FTPPermError)
+    end
 
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:stat).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.status }.should raise_error(Net::FTPTempError)
-  end
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:stat).and_respond("502 Command not implemented.")
+      -> { @ftp.status }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:stat).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.status }.should raise_error(Net::FTPTempError)
+    end
 
-  it "raises a Net::FTPPermError when the response code is 530" do
-    @server.should_receive(:stat).and_respond("530 Requested action not taken.")
-    -> { @ftp.status }.should raise_error(Net::FTPPermError)
+    it "raises a Net::FTPPermError when the response code is 530" do
+      @server.should_receive(:stat).and_respond("530 Requested action not taken.")
+      -> { @ftp.status }.should raise_error(Net::FTPPermError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/storbinary_spec.rb b/spec/ruby/library/net/ftp/storbinary_spec.rb
index eb65db1e8d..64c9090760 100644
--- a/spec/ruby/library/net/ftp/storbinary_spec.rb
+++ b/spec/ruby/library/net/ftp/storbinary_spec.rb
@@ -1,48 +1,51 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#storbinary" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @local_fixture_file  = File.dirname(__FILE__) + "/fixtures/putbinaryfile"
-    @tmp_file = tmp("binaryfile", false)
+  describe "Net::FTP#storbinary" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+      @local_fixture_file  = File.dirname(__FILE__) + "/fixtures/putbinaryfile"
+      @tmp_file = tmp("binaryfile", false)
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-    rm_r @tmp_file
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
 
-  it "sends the passed command and the passed File object's content to the server" do
-    File.open(@local_fixture_file) do |f|
-      f.binmode
+      rm_r @tmp_file
+    end
+
+    it "sends the passed command and the passed File object's content to the server" do
+      File.open(@local_fixture_file) do |f|
+        f.binmode
 
-      @ftp.storbinary("STOR binary", f, 4096) {}
-      @ftp.last_response.should == "200 OK, Data received. (STOR binary)\n"
+        @ftp.storbinary("STOR binary", f, 4096) {}
+        @ftp.last_response.should == "200 OK, Data received. (STOR binary)\n"
+      end
     end
-  end
 
-  it "yields the transmitted content as binary blocks of the passed size" do
-    File.open(@local_fixture_file) do |f|
-      f.binmode
-
-      res = []
-      @ftp.storbinary("STOR binary", f, 10) { |x| res << x }
-      res.should == [
-        "This is an", " example f",
-        "ile\nwhich ", "is going t",
-        "o be trans", "mitted\nusi",
-        "ng #putbin", "aryfile.\n"
-      ]
+    it "yields the transmitted content as binary blocks of the passed size" do
+      File.open(@local_fixture_file) do |f|
+        f.binmode
+
+        res = []
+        @ftp.storbinary("STOR binary", f, 10) { |x| res << x }
+        res.should == [
+          "This is an", " example f",
+          "ile\nwhich ", "is going t",
+          "o be trans", "mitted\nusi",
+          "ng #putbin", "aryfile.\n"
+        ]
+      end
     end
   end
 end
diff --git a/spec/ruby/library/net/ftp/storlines_spec.rb b/spec/ruby/library/net/ftp/storlines_spec.rb
index 4affa37eee..a4bb7af799 100644
--- a/spec/ruby/library/net/ftp/storlines_spec.rb
+++ b/spec/ruby/library/net/ftp/storlines_spec.rb
@@ -1,43 +1,46 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#storlines" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @local_fixture_file  = File.dirname(__FILE__) + "/fixtures/puttextfile"
-    @tmp_file = tmp("textfile", false)
+  describe "Net::FTP#storlines" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+      @local_fixture_file  = File.dirname(__FILE__) + "/fixtures/puttextfile"
+      @tmp_file = tmp("textfile", false)
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
 
-    rm_r @tmp_file
-  end
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
 
-  it "sends the passed command and the passed File object's content to the server" do
-    File.open(@local_fixture_file) do |f|
-      @ftp.storlines("STOR text", f) {}
-      @ftp.last_response.should == "200 OK, Data received. (STOR text)\n"
+      rm_r @tmp_file
+    end
+
+    it "sends the passed command and the passed File object's content to the server" do
+      File.open(@local_fixture_file) do |f|
+        @ftp.storlines("STOR text", f) {}
+        @ftp.last_response.should == "200 OK, Data received. (STOR text)\n"
+      end
     end
-  end
 
-  it "yields each line of the transmitted content" do
-    File.open(@local_fixture_file) do |f|
-      res = []
-      @ftp.storlines("STOR text", f) { |x| res << x }
-      res.should == [
-        "This is an example file\r\n",
-        "which is going to be transmitted\r\n",
-        "using #puttextfile.\r\n"
-      ]
+    it "yields each line of the transmitted content" do
+      File.open(@local_fixture_file) do |f|
+        res = []
+        @ftp.storlines("STOR text", f) { |x| res << x }
+        res.should == [
+          "This is an example file\r\n",
+          "which is going to be transmitted\r\n",
+          "using #puttextfile.\r\n"
+        ]
+      end
     end
   end
 end
diff --git a/spec/ruby/library/net/ftp/system_spec.rb b/spec/ruby/library/net/ftp/system_spec.rb
index 749258622d..0630bbe1f6 100644
--- a/spec/ruby/library/net/ftp/system_spec.rb
+++ b/spec/ruby/library/net/ftp/system_spec.rb
@@ -1,48 +1,51 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#system" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the SYST command to the server" do
-    @ftp.system
-    @ftp.last_response.should =~ /\A215 FTP Dummy Server \(SYST\)\Z/
-  end
-
-  it "returns the received information" do
-    @ftp.system.should =~ /\AFTP Dummy Server \(SYST\)\Z/
-  end
-
-  it "raises a Net::FTPPermError when the response code is 500" do
-    @server.should_receive(:syst).and_respond("500 Syntax error, command unrecognized.")
-    -> { @ftp.system }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 501" do
-    @server.should_receive(:syst).and_respond("501 Syntax error in parameters or arguments.")
-    -> { @ftp.system }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 502" do
-    @server.should_receive(:syst).and_respond("502 Command not implemented.")
-    -> { @ftp.system }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 421" do
-    @server.should_receive(:syst).and_respond("421 Service not available, closing control connection.")
-    -> { @ftp.system }.should raise_error(Net::FTPTempError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#system" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the SYST command to the server" do
+      @ftp.system
+      @ftp.last_response.should =~ /\A215 FTP Dummy Server \(SYST\)\Z/
+    end
+
+    it "returns the received information" do
+      @ftp.system.should =~ /\AFTP Dummy Server \(SYST\)\Z/
+    end
+
+    it "raises a Net::FTPPermError when the response code is 500" do
+      @server.should_receive(:syst).and_respond("500 Syntax error, command unrecognized.")
+      -> { @ftp.system }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 501" do
+      @server.should_receive(:syst).and_respond("501 Syntax error in parameters or arguments.")
+      -> { @ftp.system }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 502" do
+      @server.should_receive(:syst).and_respond("502 Command not implemented.")
+      -> { @ftp.system }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 421" do
+      @server.should_receive(:syst).and_respond("421 Service not available, closing control connection.")
+      -> { @ftp.system }.should raise_error(Net::FTPTempError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/voidcmd_spec.rb b/spec/ruby/library/net/ftp/voidcmd_spec.rb
index 3673c7fd5b..ee74455d63 100644
--- a/spec/ruby/library/net/ftp/voidcmd_spec.rb
+++ b/spec/ruby/library/net/ftp/voidcmd_spec.rb
@@ -1,54 +1,57 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#voidcmd" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
-
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
-
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
-
-  it "sends the passed command to the server" do
-    @server.should_receive(:help).and_respond("2xx Does not raise.")
-    -> { @ftp.voidcmd("HELP") }.should_not raise_error
-  end
-
-  it "returns nil" do
-    @server.should_receive(:help).and_respond("2xx Does not raise.")
-    @ftp.voidcmd("HELP").should be_nil
-  end
-
-  it "raises a Net::FTPReplyError when the response code is 1xx" do
-    @server.should_receive(:help).and_respond("1xx Does raise a Net::FTPReplyError.")
-    -> { @ftp.voidcmd("HELP")  }.should raise_error(Net::FTPReplyError)
-  end
-
-  it "raises a Net::FTPReplyError when the response code is 3xx" do
-    @server.should_receive(:help).and_respond("3xx Does raise a Net::FTPReplyError.")
-    -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPReplyError)
-  end
-
-  it "raises a Net::FTPTempError when the response code is 4xx" do
-    @server.should_receive(:help).and_respond("4xx Does raise a Net::FTPTempError.")
-    -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPTempError)
-  end
-
-  it "raises a Net::FTPPermError when the response code is 5xx" do
-    @server.should_receive(:help).and_respond("5xx Does raise a Net::FTPPermError.")
-    -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPPermError)
-  end
-
-  it "raises a Net::FTPProtoError when the response code is not valid" do
-    @server.should_receive(:help).and_respond("999 Does raise a Net::FTPProtoError.")
-    -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPProtoError)
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
+
+  describe "Net::FTP#voidcmd" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
+
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
+
+    it "sends the passed command to the server" do
+      @server.should_receive(:help).and_respond("2xx Does not raise.")
+      -> { @ftp.voidcmd("HELP") }.should_not raise_error
+    end
+
+    it "returns nil" do
+      @server.should_receive(:help).and_respond("2xx Does not raise.")
+      @ftp.voidcmd("HELP").should be_nil
+    end
+
+    it "raises a Net::FTPReplyError when the response code is 1xx" do
+      @server.should_receive(:help).and_respond("1xx Does raise a Net::FTPReplyError.")
+      -> { @ftp.voidcmd("HELP")  }.should raise_error(Net::FTPReplyError)
+    end
+
+    it "raises a Net::FTPReplyError when the response code is 3xx" do
+      @server.should_receive(:help).and_respond("3xx Does raise a Net::FTPReplyError.")
+      -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPReplyError)
+    end
+
+    it "raises a Net::FTPTempError when the response code is 4xx" do
+      @server.should_receive(:help).and_respond("4xx Does raise a Net::FTPTempError.")
+      -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPTempError)
+    end
+
+    it "raises a Net::FTPPermError when the response code is 5xx" do
+      @server.should_receive(:help).and_respond("5xx Does raise a Net::FTPPermError.")
+      -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPPermError)
+    end
+
+    it "raises a Net::FTPProtoError when the response code is not valid" do
+      @server.should_receive(:help).and_respond("999 Does raise a Net::FTPProtoError.")
+      -> { @ftp.voidcmd("HELP") }.should raise_error(Net::FTPProtoError)
+    end
   end
 end
diff --git a/spec/ruby/library/net/ftp/welcome_spec.rb b/spec/ruby/library/net/ftp/welcome_spec.rb
index a0d7483949..e5414ef607 100644
--- a/spec/ruby/library/net/ftp/welcome_spec.rb
+++ b/spec/ruby/library/net/ftp/welcome_spec.rb
@@ -1,25 +1,28 @@
 require_relative '../../../spec_helper'
-require_relative 'spec_helper'
-require_relative 'fixtures/server'
 
-describe "Net::FTP#welcome" do
-  before :each do
-    @server = NetFTPSpecs::DummyFTP.new
-    @server.serve_once
+ruby_version_is ""..."3.1" do
+  require_relative 'spec_helper'
+  require_relative 'fixtures/server'
 
-    @ftp = Net::FTP.new
-    @ftp.connect(@server.hostname, @server.server_port)
-  end
+  describe "Net::FTP#welcome" do
+    before :each do
+      @server = NetFTPSpecs::DummyFTP.new
+      @server.serve_once
 
-  after :each do
-    @ftp.quit rescue nil
-    @ftp.close
-    @server.stop
-  end
+      @ftp = Net::FTP.new
+      @ftp.connect(@server.hostname, @server.server_port)
+    end
+
+    after :each do
+      @ftp.quit rescue nil
+      @ftp.close
+      @server.stop
+    end
 
-  it "returns the server's welcome message" do
-    @ftp.welcome.should be_nil
-    @ftp.login
-    @ftp.welcome.should == "230 User logged in, proceed. (USER anonymous)\n"
+    it "returns the server's welcome message" do
+      @ftp.welcome.should be_nil
+      @ftp.login
+      @ftp.welcome.should == "230 User logged in, proceed. (USER anonymous)\n"
+    end
   end
 end
diff --git a/spec/ruby/library/prime/each_spec.rb b/spec/ruby/library/prime/each_spec.rb
index b99cf7cf0e..c89e871582 100644
--- a/spec/ruby/library/prime/each_spec.rb
+++ b/spec/ruby/library/prime/each_spec.rb
@@ -1,167 +1,170 @@
 require_relative '../../spec_helper'
-require 'prime'
 
-describe :prime_each, shared: true do
-  before :each do
-    ScratchPad.record []
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
 
-  it "enumerates primes" do
-    primes = Prime.instance
-    result = []
+  describe :prime_each, shared: true do
+    before :each do
+      ScratchPad.record []
+    end
 
-    primes.each { |p|
-      result << p
-      break if p > 10
-    }
+    it "enumerates primes" do
+      primes = Prime.instance
+      result = []
 
-    result.should == [2, 3, 5, 7, 11]
-  end
+      primes.each { |p|
+        result << p
+        break if p > 10
+      }
 
-  it "yields ascending primes to the block" do
-    previous = 1
-    @object.each do |prime|
-      break if prime > 1000
-      ScratchPad << prime
-      prime.should > previous
-      previous = prime
+      result.should == [2, 3, 5, 7, 11]
     end
 
-    all_prime = true
-    ScratchPad.recorded.all? do |prime|
-      all_prime &&= (2..Math.sqrt(prime)).all? { |d| prime % d != 0 }
+    it "yields ascending primes to the block" do
+      previous = 1
+      @object.each do |prime|
+        break if prime > 1000
+        ScratchPad << prime
+        prime.should > previous
+        previous = prime
+      end
+
+      all_prime = true
+      ScratchPad.recorded.all? do |prime|
+        all_prime &&= (2..Math.sqrt(prime)).all? { |d| prime % d != 0 }
+      end
+
+      all_prime.should be_true
     end
 
-    all_prime.should be_true
-  end
+    it "returns the last evaluated expression in the passed block" do
+      @object.each { break :value }.should equal(:value)
+    end
 
-  it "returns the last evaluated expression in the passed block" do
-    @object.each { break :value }.should equal(:value)
-  end
+    describe "when not passed a block" do
+      before :each do
+        @prime_enum = @object.each
+      end
 
-  describe "when not passed a block" do
-    before :each do
-      @prime_enum = @object.each
-    end
+      it "returns an object that is Enumerable" do
+        @prime_enum.each.should be_kind_of(Enumerable)
+      end
 
-    it "returns an object that is Enumerable" do
-      @prime_enum.each.should be_kind_of(Enumerable)
-    end
+      it "returns an object that responds to #with_index" do
+        @prime_enum.should respond_to(:with_index)
+      end
 
-    it "returns an object that responds to #with_index" do
-      @prime_enum.should respond_to(:with_index)
-    end
+      it "returns an object that responds to #with_object" do
+        @prime_enum.should respond_to(:with_object)
+      end
 
-    it "returns an object that responds to #with_object" do
-      @prime_enum.should respond_to(:with_object)
-    end
+      it "returns an object that responds to #next" do
+        @prime_enum.should respond_to(:next)
+      end
 
-    it "returns an object that responds to #next" do
-      @prime_enum.should respond_to(:next)
-    end
+      it "returns an object that responds to #rewind" do
+        @prime_enum.should respond_to(:rewind)
+      end
 
-    it "returns an object that responds to #rewind" do
-      @prime_enum.should respond_to(:rewind)
-    end
+      it "yields primes starting at 2 independent of prior enumerators" do
+        @prime_enum.next.should == 2
+        @prime_enum.next.should == 3
 
-    it "yields primes starting at 2 independent of prior enumerators" do
-      @prime_enum.next.should == 2
-      @prime_enum.next.should == 3
+        @object.each { |prime| break prime }.should == 2
+      end
 
-      @object.each { |prime| break prime }.should == 2
+      it "returns an enumerator that yields previous primes when #rewind is called" do
+        @prime_enum.next.should == 2
+        @prime_enum.next.should == 3
+        @prime_enum.rewind
+        @prime_enum.next.should == 2
+      end
+
+      it "returns independent enumerators" do
+        enum = @object.each
+        enum.next.should == 2
+        enum.next.should == 3
+
+        @prime_enum.next.should == 2
+
+        enum.next.should == 5
+      end
     end
+  end
 
-    it "returns an enumerator that yields previous primes when #rewind is called" do
-      @prime_enum.next.should == 2
-      @prime_enum.next.should == 3
-      @prime_enum.rewind
-      @prime_enum.next.should == 2
+  describe :prime_each_with_arguments, shared: true do
+    before :each do
+      ScratchPad.record []
     end
 
-    it "returns independent enumerators" do
-      enum = @object.each
-      enum.next.should == 2
-      enum.next.should == 3
+    it "yields ascending primes less than or equal to the argument" do
+      bound = 1000
+      previous = 1
+      @object.each(bound) do |prime|
+        ScratchPad << prime
+        prime.should > previous
+        previous = prime
+      end
 
-      @prime_enum.next.should == 2
+      ScratchPad.recorded.all? do |prime|
+        (2..Math.sqrt(prime)).all? { |d| prime % d != 0 }
+      end.should be_true
 
-      enum.next.should == 5
+      ScratchPad.recorded.all? { |prime| prime <= bound }.should be_true
     end
-  end
-end
 
-describe :prime_each_with_arguments, shared: true do
-  before :each do
-    ScratchPad.record []
-  end
+    it "returns nil when no prime is generated" do
+      @object.each(1) { :value }.should be_nil
+    end
 
-  it "yields ascending primes less than or equal to the argument" do
-    bound = 1000
-    previous = 1
-    @object.each(bound) do |prime|
-      ScratchPad << prime
-      prime.should > previous
-      previous = prime
+    it "yields primes starting at 2 independent of prior enumeration" do
+      @object.each(10) { |prime| prime }.should == 7
+      @object.each(10) { |prime| break prime }.should == 2
     end
 
-    ScratchPad.recorded.all? do |prime|
-      (2..Math.sqrt(prime)).all? { |d| prime % d != 0 }
-    end.should be_true
+    it "accepts a pseudo-prime generator as the second argument" do
+      generator = mock('very bad pseudo-prime generator')
+      generator.should_receive(:upper_bound=).with(100)
+      generator.should_receive(:each).and_yield(2).and_yield(3).and_yield(4)
 
-    ScratchPad.recorded.all? { |prime| prime <= bound }.should be_true
-  end
+      @object.each(100, generator) { |prime| ScratchPad << prime }
+      ScratchPad.recorded.should == [2, 3, 4]
+    end
 
-  it "returns nil when no prime is generated" do
-    @object.each(1) { :value }.should be_nil
+    describe "when not passed a block" do
+      it "returns an object that returns primes less than or equal to the bound" do
+        bound = 100
+        @object.each(bound).all? { |prime| prime <= bound }.should be_true
+      end
+    end
   end
 
-  it "yields primes starting at 2 independent of prior enumeration" do
-    @object.each(10) { |prime| prime }.should == 7
-    @object.each(10) { |prime| break prime }.should == 2
+  describe "Prime.each" do
+    it_behaves_like :prime_each, :each, Prime
   end
 
-  it "accepts a pseudo-prime generator as the second argument" do
-    generator = mock('very bad pseudo-prime generator')
-    generator.should_receive(:upper_bound=).with(100)
-    generator.should_receive(:each).and_yield(2).and_yield(3).and_yield(4)
-
-    @object.each(100, generator) { |prime| ScratchPad << prime }
-    ScratchPad.recorded.should == [2, 3, 4]
+  describe "Prime.each" do
+    it_behaves_like :prime_each_with_arguments, :each, Prime
   end
 
-  describe "when not passed a block" do
-    it "returns an object that returns primes less than or equal to the bound" do
-      bound = 100
-      @object.each(bound).all? { |prime| prime <= bound }.should be_true
-    end
+  describe "Prime#each with Prime.instance" do
+    it_behaves_like :prime_each, :each, Prime.instance
   end
-end
 
-describe "Prime.each" do
-  it_behaves_like :prime_each, :each, Prime
-end
-
-describe "Prime.each" do
-  it_behaves_like :prime_each_with_arguments, :each, Prime
-end
-
-describe "Prime#each with Prime.instance" do
-  it_behaves_like :prime_each, :each, Prime.instance
-end
-
-describe "Prime#each with Prime.instance" do
-  it_behaves_like :prime_each_with_arguments, :each, Prime.instance
-end
-
-describe "Prime#each with Prime.instance" do
-  before :each do
-    @object = Prime.instance
+  describe "Prime#each with Prime.instance" do
+    it_behaves_like :prime_each_with_arguments, :each, Prime.instance
   end
 
-  it_behaves_like :prime_each, :each
+  describe "Prime#each with Prime.instance" do
+    before :each do
+      @object = Prime.instance
+    end
+
+    it_behaves_like :prime_each, :each
 
-  it "resets the enumerator with each call" do
-    @object.each { |prime| break if prime > 10 }
-    @object.each { |prime| break prime }.should == 2
+    it "resets the enumerator with each call" do
+      @object.each { |prime| break if prime > 10 }
+      @object.each { |prime| break prime }.should == 2
+    end
   end
 end
diff --git a/spec/ruby/library/prime/instance_spec.rb b/spec/ruby/library/prime/instance_spec.rb
index 5183f36901..82f21913b7 100644
--- a/spec/ruby/library/prime/instance_spec.rb
+++ b/spec/ruby/library/prime/instance_spec.rb
@@ -1,21 +1,24 @@
 require_relative '../../spec_helper'
-require 'prime'
 
-describe "Prime.instance" do
-  it "returns a object representing the set of prime numbers" do
-    Prime.instance.should be_kind_of(Prime)
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
 
-  it "returns a object with no obsolete features" do
-    Prime.instance.should_not respond_to(:succ)
-    Prime.instance.should_not respond_to(:next)
-  end
+  describe "Prime.instance" do
+    it "returns a object representing the set of prime numbers" do
+      Prime.instance.should be_kind_of(Prime)
+    end
 
-  it "does not complain anything" do
-    -> { Prime.instance }.should_not complain
-  end
+    it "returns a object with no obsolete features" do
+      Prime.instance.should_not respond_to(:succ)
+      Prime.instance.should_not respond_to(:next)
+    end
+
+    it "does not complain anything" do
+      -> { Prime.instance }.should_not complain
+    end
 
-  it "raises a ArgumentError when is called with some arguments" do
-    -> { Prime.instance(1) }.should raise_error(ArgumentError)
+    it "raises a ArgumentError when is called with some arguments" do
+      -> { Prime.instance(1) }.should raise_error(ArgumentError)
+    end
   end
 end
diff --git a/spec/ruby/library/prime/int_from_prime_division_spec.rb b/spec/ruby/library/prime/int_from_prime_division_spec.rb
index 5abb7221df..5c881aefa1 100644
--- a/spec/ruby/library/prime/int_from_prime_division_spec.rb
+++ b/spec/ruby/library/prime/int_from_prime_division_spec.rb
@@ -1,13 +1,16 @@
 require_relative '../../spec_helper'
-require 'prime'
 
-describe "Prime.int_from_prime_division" do
-  it "returns the product of the given factorization" do
-    Prime.int_from_prime_division([[2,3], [3,3], [5,3], [7,3], [11,3], [13,3], [17,3]]).
-      should == 2**3 * 3**3 * 5**3 * 7**3 * 11**3 * 13**3 * 17**3
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
+
+  describe "Prime.int_from_prime_division" do
+    it "returns the product of the given factorization" do
+      Prime.int_from_prime_division([[2,3], [3,3], [5,3], [7,3], [11,3], [13,3], [17,3]]).
+        should == 2**3 * 3**3 * 5**3 * 7**3 * 11**3 * 13**3 * 17**3
+    end
 
-  it "returns 1 for an empty factorization" do
-    Prime.int_from_prime_division([]).should == 1
+    it "returns 1 for an empty factorization" do
+      Prime.int_from_prime_division([]).should == 1
+    end
   end
 end
diff --git a/spec/ruby/library/prime/integer/each_prime_spec.rb b/spec/ruby/library/prime/integer/each_prime_spec.rb
index a71296b0df..6034802e73 100644
--- a/spec/ruby/library/prime/integer/each_prime_spec.rb
+++ b/spec/ruby/library/prime/integer/each_prime_spec.rb
@@ -1,13 +1,16 @@
 require_relative '../../../spec_helper'
-require 'prime'
 
-describe "Integer.each_prime" do
-  it "is transferred to Prime.each" do
-    Prime.should_receive(:each).with(100).and_yield(2).and_yield(3).and_yield(5)
-    yielded = []
-    Integer.each_prime(100) do |prime|
-      yielded << prime
+ruby_version_is ""..."3.1" do
+  require 'prime'
+
+  describe "Integer.each_prime" do
+    it "is transferred to Prime.each" do
+      Prime.should_receive(:each).with(100).and_yield(2).and_yield(3).and_yield(5)
+      yielded = []
+      Integer.each_prime(100) do |prime|
+        yielded << prime
+      end
+      yielded.should == [2,3,5]
     end
-    yielded.should == [2,3,5]
   end
 end
diff --git a/spec/ruby/library/prime/integer/from_prime_division_spec.rb b/spec/ruby/library/prime/integer/from_prime_division_spec.rb
index e0e74fb336..5422bc651c 100644
--- a/spec/ruby/library/prime/integer/from_prime_division_spec.rb
+++ b/spec/ruby/library/prime/integer/from_prime_division_spec.rb
@@ -1,13 +1,16 @@
 require_relative '../../../spec_helper'
-require 'prime'
 
-describe "Integer.from_prime_division" do
-  it "returns the product of the given factorization" do
-    Integer.from_prime_division([[2,3], [3,3], [5,3], [7,3], [11,3], [13,3], [17,3]]).
-      should == 2**3 * 3**3 * 5**3 * 7**3 * 11**3 * 13**3 * 17**3
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
+
+  describe "Integer.from_prime_division" do
+    it "returns the product of the given factorization" do
+      Integer.from_prime_division([[2,3], [3,3], [5,3], [7,3], [11,3], [13,3], [17,3]]).
+        should == 2**3 * 3**3 * 5**3 * 7**3 * 11**3 * 13**3 * 17**3
+    end
 
-  it "returns 1 for an empty factorization" do
-    Integer.from_prime_division([]).should == 1
+    it "returns 1 for an empty factorization" do
+      Integer.from_prime_division([]).should == 1
+    end
   end
 end
diff --git a/spec/ruby/library/prime/integer/prime_division_spec.rb b/spec/ruby/library/prime/integer/prime_division_spec.rb
index be03438a6f..03be0be27b 100644
--- a/spec/ruby/library/prime/integer/prime_division_spec.rb
+++ b/spec/ruby/library/prime/integer/prime_division_spec.rb
@@ -1,19 +1,22 @@
 require_relative '../../../spec_helper'
-require 'prime'
 
-describe "Integer#prime_division" do
-  it "returns an array of a prime factor and a corresponding exponent" do
-    (2*3*5*7*11*13*17).prime_division.should ==
-      [[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
 
-  it "returns an empty array for 1" do
-    1.prime_division.should == []
-  end
-  it "returns an empty array for -1" do
-    -1.prime_division.should == [[-1, 1]]
-  end
-  it "raises ZeroDivisionError for 0" do
-    -> { 0.prime_division }.should raise_error(ZeroDivisionError)
+  describe "Integer#prime_division" do
+    it "returns an array of a prime factor and a corresponding exponent" do
+      (2*3*5*7*11*13*17).prime_division.should ==
+        [[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
+    end
+
+    it "returns an empty array for 1" do
+      1.prime_division.should == []
+    end
+    it "returns an empty array for -1" do
+      -1.prime_division.should == [[-1, 1]]
+    end
+    it "raises ZeroDivisionError for 0" do
+      -> { 0.prime_division }.should raise_error(ZeroDivisionError)
+    end
   end
 end
diff --git a/spec/ruby/library/prime/integer/prime_spec.rb b/spec/ruby/library/prime/integer/prime_spec.rb
index 53de76d5ab..65b779e319 100644
--- a/spec/ruby/library/prime/integer/prime_spec.rb
+++ b/spec/ruby/library/prime/integer/prime_spec.rb
@@ -1,17 +1,20 @@
 require_relative '../../../spec_helper'
-require 'prime'
 
-describe "Integer#prime?" do
-  it "returns a true value for prime numbers" do
-    2.prime?.should be_true
-    3.prime?.should be_true
-    (2**31-1).prime?.should be_true  # 8th Mersenne prime (M8)
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
+
+  describe "Integer#prime?" do
+    it "returns a true value for prime numbers" do
+      2.prime?.should be_true
+      3.prime?.should be_true
+      (2**31-1).prime?.should be_true  # 8th Mersenne prime (M8)
+    end
 
-  it "returns a false value for composite numbers" do
-    4.prime?.should be_false
-    15.prime?.should be_false
-    (2**32-1).prime?.should be_false
-    ( (2**17-1)*(2**19-1) ).prime?.should be_false  # M6*M7
+    it "returns a false value for composite numbers" do
+      4.prime?.should be_false
+      15.prime?.should be_false
+      (2**32-1).prime?.should be_false
+      ( (2**17-1)*(2**19-1) ).prime?.should be_false  # M6*M7
+    end
   end
 end
diff --git a/spec/ruby/library/prime/next_spec.rb b/spec/ruby/library/prime/next_spec.rb
index 39c4ae16ae..8e805ed044 100644
--- a/spec/ruby/library/prime/next_spec.rb
+++ b/spec/ruby/library/prime/next_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'shared/next'
-require 'prime'
 
-describe "Prime#next" do
-  it_behaves_like :prime_next, :next
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/next'
+  require 'prime'
+
+  describe "Prime#next" do
+    it_behaves_like :prime_next, :next
+  end
 end
diff --git a/spec/ruby/library/prime/prime_division_spec.rb b/spec/ruby/library/prime/prime_division_spec.rb
index 6293478f59..4c93d5936a 100644
--- a/spec/ruby/library/prime/prime_division_spec.rb
+++ b/spec/ruby/library/prime/prime_division_spec.rb
@@ -1,25 +1,28 @@
 require_relative '../../spec_helper'
-require 'prime'
 
-describe "Prime.prime_division" do
-  it "returns an array of a prime factor and a corresponding exponent" do
-    Prime.prime_division(2*3*5*7*11*13*17).should ==
-      [[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
 
-  it "returns an empty array for 1" do
-    Prime.prime_division(1).should == []
-  end
+  describe "Prime.prime_division" do
+    it "returns an array of a prime factor and a corresponding exponent" do
+      Prime.prime_division(2*3*5*7*11*13*17).should ==
+        [[2,1], [3,1], [5,1], [7,1], [11,1], [13,1], [17,1]]
+    end
 
-  it "returns [[-1, 1]] for -1" do
-    Prime.prime_division(-1).should == [[-1, 1]]
-  end
+    it "returns an empty array for 1" do
+      Prime.prime_division(1).should == []
+    end
 
-  it "includes [[-1, 1]] in the divisors of a negative number" do
-    Prime.prime_division(-10).should include([-1, 1])
-  end
+    it "returns [[-1, 1]] for -1" do
+      Prime.prime_division(-1).should == [[-1, 1]]
+    end
+
+    it "includes [[-1, 1]] in the divisors of a negative number" do
+      Prime.prime_division(-10).should include([-1, 1])
+    end
 
-  it "raises ZeroDivisionError for 0" do
-    -> { Prime.prime_division(0) }.should raise_error(ZeroDivisionError)
+    it "raises ZeroDivisionError for 0" do
+      -> { Prime.prime_division(0) }.should raise_error(ZeroDivisionError)
+    end
   end
 end
diff --git a/spec/ruby/library/prime/prime_spec.rb b/spec/ruby/library/prime/prime_spec.rb
index 0896c7f0f3..e2afddd5b2 100644
--- a/spec/ruby/library/prime/prime_spec.rb
+++ b/spec/ruby/library/prime/prime_spec.rb
@@ -1,17 +1,20 @@
 require_relative '../../spec_helper'
-require 'prime'
 
-describe "Prime#prime?" do
-  it "returns a true value for prime numbers" do
-    Prime.prime?(2).should be_true
-    Prime.prime?(3).should be_true
-    Prime.prime?(2**31-1).should be_true  # 8th Mersenne prime (M8)
-  end
+ruby_version_is ""..."3.1" do
+  require 'prime'
+
+  describe "Prime#prime?" do
+    it "returns a true value for prime numbers" do
+      Prime.prime?(2).should be_true
+      Prime.prime?(3).should be_true
+      Prime.prime?(2**31-1).should be_true  # 8th Mersenne prime (M8)
+    end
 
-  it "returns a false value for composite numbers" do
-    Prime.prime?(4).should be_false
-    Prime.prime?(15).should be_false
-    Prime.prime?(2**32-1).should be_false
-    Prime.prime?( (2**17-1)*(2**19-1) ).should be_false  # M6*M7
+    it "returns a false value for composite numbers" do
+      Prime.prime?(4).should be_false
+      Prime.prime?(15).should be_false
+      Prime.prime?(2**32-1).should be_false
+      Prime.prime?( (2**17-1)*(2**19-1) ).should be_false  # M6*M7
+    end
   end
 end
diff --git a/spec/ruby/library/prime/succ_spec.rb b/spec/ruby/library/prime/succ_spec.rb
index 34c18d2ba0..9843dae25d 100644
--- a/spec/ruby/library/prime/succ_spec.rb
+++ b/spec/ruby/library/prime/succ_spec.rb
@@ -1,7 +1,10 @@
 require_relative '../../spec_helper'
-require_relative 'shared/next'
-require 'prime'
 
-describe "Prime#succ" do
-  it_behaves_like :prime_next, :succ
+ruby_version_is ""..."3.1" do
+  require_relative 'shared/next'
+  require 'prime'
+
+  describe "Prime#succ" do
+    it_behaves_like :prime_next, :succ
+  end
 end