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diff --git a/spec/rubyspec/library/matrix/minus_spec.rb b/spec/rubyspec/library/matrix/minus_spec.rb
new file mode 100644
index 0000000000..fe2d716882
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+++ b/spec/rubyspec/library/matrix/minus_spec.rb
@@ -0,0 +1,42 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+require 'matrix'
+
+describe "Matrix#-" do
+  before :each do
+    @a = Matrix[ [1, 2], [3, 4] ]
+    @b = Matrix[ [4, 5], [6, 7] ]
+  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 "returns an instance of Matrix" do
+    (@a - @b).should be_kind_of(Matrix)
+  end
+
+  it "raises a Matrix::ErrDimensionMismatch if the matrices are different sizes" do
+    lambda { @a - Matrix[ [1] ] }.should raise_error(Matrix::ErrDimensionMismatch)
+  end
+
+  it "raises a ExceptionForMatrix::ErrOperationNotDefined if other is a Numeric Type" do
+    lambda { @a - 2            }.should raise_error(Matrix::ErrOperationNotDefined)
+    lambda { @a - 1.2          }.should raise_error(Matrix::ErrOperationNotDefined)
+    lambda { @a - bignum_value }.should raise_error(Matrix::ErrOperationNotDefined)
+  end
+
+  it "raises a TypeError if other is of wrong type" do
+    lambda { @a - nil        }.should raise_error(TypeError)
+    lambda { @a - "a"        }.should raise_error(TypeError)
+    lambda { @a - [ [1, 2] ] }.should raise_error(TypeError)
+    lambda { @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)
+    end
+  end
+end