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, 226 insertions, 0 deletions

diff --git a/spec/rubyspec/language/optional_assignments_spec.rb b/spec/rubyspec/language/optional_assignments_spec.rb
new file mode 100644
index 0000000000..c104d08253
--- /dev/null
+++ b/spec/rubyspec/language/optional_assignments_spec.rb
@@ -0,0 +1,226 @@
+require File.expand_path('../../spec_helper', __FILE__)
+
+describe 'Optional variable assignments' do
+  describe 'using ||=' do
+    describe 'using a single variable' do
+      it 'assigns a new variable' do
+        a ||= 10
+
+        a.should == 10
+      end
+
+      it 're-assigns an existing variable set to false' do
+        a = false
+        a ||= 10
+
+        a.should == 10
+      end
+
+      it 're-assigns an existing variable set to nil' do
+        a = nil
+        a ||= 10
+
+        a.should == 10
+      end
+
+      it 'does not re-assign a variable with a truthy value' do
+        a = 10
+        a ||= 20
+
+        a.should == 10
+      end
+
+      it 'does not evaluate the right side when not needed' do
+        a = 10
+        a ||= raise('should not be executed')
+        a.should == 10
+      end
+
+      it 'does not re-assign a variable with a truthy value when using an inline rescue' do
+        a = 10
+        a ||= 20 rescue 30
+
+        a.should == 10
+      end
+    end
+
+    describe 'using a accessor' do
+      before do
+        klass = Class.new { attr_accessor :b }
+        @a    = klass.new
+      end
+
+      it 'assigns a new variable' do
+        @a.b ||= 10
+
+        @a.b.should == 10
+      end
+
+      it 're-assigns an existing variable set to false' do
+        @a.b = false
+        @a.b ||= 10
+
+        @a.b.should == 10
+      end
+
+      it 're-assigns an existing variable set to nil' do
+        @a.b = nil
+        @a.b ||= 10
+
+        @a.b.should == 10
+      end
+
+      it 'does not re-assign a variable with a truthy value' do
+        @a.b = 10
+        @a.b ||= 20
+
+        @a.b.should == 10
+      end
+
+      it 'does not evaluate the right side when not needed' do
+        @a.b = 10
+        @a.b ||= raise('should not be executed')
+        @a.b.should == 10
+      end
+
+      it 'does not re-assign a variable with a truthy value when using an inline rescue' do
+        @a.b = 10
+        @a.b ||= 20 rescue 30
+
+        @a.b.should == 10
+      end
+    end
+  end
+
+  describe 'using &&=' do
+    describe 'using a single variable' do
+      it 'leaves new variable unassigned' do
+        a &&= 10
+
+        a.should == nil
+      end
+
+      it 'leaves false' do
+        a = false
+        a &&= 10
+
+        a.should == false
+      end
+
+      it 'leaves nil' do
+        a = nil
+        a &&= 10
+
+        a.should == nil
+      end
+
+      it 'does not evaluate the right side when not needed' do
+        a = nil
+        a &&= raise('should not be executed')
+        a.should == nil
+      end
+
+      it 'does re-assign a variable with a truthy value' do
+        a = 10
+        a &&= 20
+
+        a.should == 20
+      end
+
+      it 'does re-assign a variable with a truthy value when using an inline rescue' do
+        a = 10
+        a &&= 20 rescue 30
+
+        a.should == 20
+      end
+    end
+
+    describe 'using a single variable' do
+      before do
+        klass = Class.new { attr_accessor :b }
+        @a    = klass.new
+      end
+
+      it 'leaves new variable unassigned' do
+        @a.b &&= 10
+
+        @a.b.should == nil
+      end
+
+      it 'leaves false' do
+        @a.b = false
+        @a.b &&= 10
+
+        @a.b.should == false
+      end
+
+      it 'leaves nil' do
+        @a.b = nil
+        @a.b &&= 10
+
+        @a.b.should == nil
+      end
+
+      it 'does not evaluate the right side when not needed' do
+        @a.b = nil
+        @a.b &&= raise('should not be executed')
+        @a.b.should == nil
+      end
+
+      it 'does re-assign a variable with a truthy value' do
+        @a.b = 10
+        @a.b &&= 20
+
+        @a.b.should == 20
+      end
+
+      it 'does re-assign a variable with a truthy value when using an inline rescue' do
+        @a.b = 10
+        @a.b &&= 20 rescue 30
+
+        @a.b.should == 20
+      end
+    end
+  end
+
+  describe 'using compunded constants' do
+    before do
+      Object.send(:remove_const, :A) if defined? Object::A
+    end
+
+    it 'with ||= assignments' do
+      Object::A ||= 10
+      Object::A.should == 10
+    end
+
+    it 'with ||= do not reassign' do
+      Object::A = 20
+      Object::A ||= 10
+      Object::A.should == 20
+    end
+
+    it 'with &&= assignments' do
+      Object::A = 20
+      -> {
+        Object::A &&= 10
+      }.should complain(/already initialized constant/)
+      Object::A.should == 10
+    end
+
+    it 'with &&= assignments will fail with non-existant constants' do
+      lambda { Object::A &&= 10 }.should raise_error(NameError)
+    end
+
+    it 'with operator assignments' do
+      Object::A = 20
+      -> {
+        Object::A += 10
+      }.should complain(/already initialized constant/)
+      Object::A.should == 30
+    end
+
+    it 'with operator assignments will fail with non-existant constants' do
+      lambda { Object::A += 10 }.should raise_error(NameError)
+    end
+  end
+end