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

spec/rubyspec/library/rexml/element/delete_namespace_spec.rb

@@ -0,0 +1,25 @@
+require 'rexml/document'
+require File.expand_path('../../../../spec_helper', __FILE__)
+
+describe "REXML::Element#delete_namespace" do
+
+  before :each do
+    @doc = REXML::Document.new "<a xmlns:foo='bar' xmlns='twiddle'/>"
+  end
+
+  it "deletes a namespace from the element" do
+    @doc.root.delete_namespace 'foo'
+    @doc.root.namespace("foo").should be_nil
+    @doc.root.to_s.should == "<a xmlns='twiddle'/>"
+  end
+
+  it "deletes default namespace when called with no args" do
+    @doc.root.delete_namespace
+    @doc.root.namespace.should be_empty
+    @doc.root.to_s.should == "<a xmlns:foo='bar'/>"
+  end
+
+  it "returns the element" do
+    @doc.root.delete_namespace.should == @doc.root
+  end
+end