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, 15 insertions, 0 deletions

diff --git a/spec/rubyspec/library/set/sortedset/shared/difference.rb b/spec/rubyspec/library/set/sortedset/shared/difference.rb
new file mode 100644
index 0000000000..ec57015ac2
--- /dev/null
+++ b/spec/rubyspec/library/set/sortedset/shared/difference.rb
@@ -0,0 +1,15 @@
+describe :sorted_set_difference, shared: true do
+  before :each do
+    @set = SortedSet["a", "b", "c"]
+  end
+
+  it "returns a new SortedSet containting self's elements excluding the elements in the passed Enumerable" do
+    @set.send(@method, SortedSet["a", "b"]).should == SortedSet["c"]
+    @set.send(@method, ["b", "c"]).should == SortedSet["a"]
+  end
+
+  it "raises an ArgumentError when passed a non-Enumerable" do
+    lambda { @set.send(@method, 1) }.should raise_error(ArgumentError)
+    lambda { @set.send(@method, Object.new) }.should raise_error(ArgumentError)
+  end
+end