Add in-tree mspec and ruby/spec

* For easier modifications of ruby/spec by MRI developers.
* .gitignore: track changes under spec.
* spec/mspec, spec/rubyspec: add in-tree mspec and ruby/spec.
  These files can therefore be updated like any other file in MRI.
  Instructions are provided in spec/README.
  [Feature #13156] [ruby-core:79246]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58595 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 12 insertions, 0 deletions

diff --git a/spec/rubyspec/library/matrix/shared/trace.rb b/spec/rubyspec/library/matrix/shared/trace.rb
new file mode 100644
index 0000000000..2a42839f5d
--- /dev/null
+++ b/spec/rubyspec/library/matrix/shared/trace.rb
@@ -0,0 +1,12 @@
+require 'matrix'
+
+describe :trace, shared: true do
+  it "returns the sum of diagonal elements in a square Matrix" do
+    Matrix[[7,6], [3,9]].trace.should == 16
+  end
+
+  it "returns the sum of diagonal elements in a rectangular Matrix" do
+    lambda{ Matrix[[1,2,3], [4,5,6]].trace}.should raise_error(Matrix::ErrDimensionMismatch)
+  end
+
+end