1 files changed, 143 insertions, 0 deletions
diff --git a/spec/ruby/language/metaclass_spec.rb b/spec/ruby/language/metaclass_spec.rb
new file mode 100644
index 0000000000..b3bcd9ef18
--- /dev/null
+++ b/spec/ruby/language/metaclass_spec.rb
@@ -0,0 +1,143 @@
+require File.expand_path('../../spec_helper', __FILE__)
+require File.expand_path('../../fixtures/class', __FILE__)
+require File.expand_path('../fixtures/metaclass', __FILE__)
+
+describe "self in a metaclass body (class << obj)" do
+  it "is TrueClass for true" do
+    class << true; self; end.should == TrueClass
+  end
+
+  it "is FalseClass for false" do
+    class << false; self; end.should == FalseClass
+  end
+
+  it "is NilClass for nil" do
+    class << nil; self; end.should == NilClass
+  end
+
+  it "raises a TypeError for numbers" do
+    lambda { class << 1; self; end }.should raise_error(TypeError)
+  end
+
+  it "raises a TypeError for symbols" do
+    lambda { class << :symbol; self; end }.should raise_error(TypeError)
+  end
+
+  it "is a singleton Class instance" do
+    cls = class << mock('x'); self; end
+    cls.is_a?(Class).should == true
+    cls.should_not equal(Object)
+  end
+end
+
+describe "A constant on a metaclass" do
+  before :each do
+    @object = Object.new
+    class << @object
+      CONST = self
+    end
+  end
+
+  it "can be accessed after the metaclass body is reopened" do
+    class << @object
+      CONST.should == self
+    end
+  end
+
+  it "can be accessed via self::CONST" do
+    class << @object
+      self::CONST.should == self
+    end
+  end
+
+  it "can be accessed via const_get" do
+    class << @object
+      const_get(:CONST).should == self
+    end
+  end
+
+  it "is not defined on the object's class" do
+    @object.class.const_defined?(:CONST).should be_false
+  end
+
+  it "is not defined in the metaclass opener's scope" do
+    class << @object
+      CONST
+    end
+    lambda { CONST }.should raise_error(NameError)
+  end
+
+  it "cannot be accessed via object::CONST" do
+    lambda do
+      @object::CONST
+    end.should raise_error(TypeError)
+  end
+
+  it "raises a NameError for anonymous_module::CONST" do
+    @object = Class.new
+    class << @object
+      CONST = 100
+    end
+
+    lambda do
+      @object::CONST
+    end.should raise_error(NameError)
+  end
+
+  it "appears in the metaclass constant list" do
+    constants = class << @object; constants; end
+    constants.should include(:CONST)
+  end
+
+  it "does not appear in the object's class constant list" do
+    @object.class.constants.should_not include(:CONST)
+  end
+
+  it "is not preserved when the object is duped" do
+    @object = @object.dup
+
+    lambda do
+      class << @object; CONST; end
+    end.should raise_error(NameError)
+  end
+
+  it "is preserved when the object is cloned" do
+    @object = @object.clone
+
+    class << @object
+      CONST.should_not be_nil
+    end
+  end
+end
+
+describe "calling methods on the metaclass" do
+
+  it "calls a method on the metaclass" do
+    MetaClassSpecs::A.cheese.should == 'edam'
+    MetaClassSpecs::B.cheese.should == 'stilton'
+  end
+
+  it "calls a method on the instance's metaclass" do
+    b = MetaClassSpecs::B.new
+    b_meta = MetaClassSpecs.metaclass_of b
+    b_meta.send(:define_method, :cheese) {'cheshire'}
+    b.cheese.should == 'cheshire'
+  end
+
+  it "calls a method in deeper chains of metaclasses" do
+    b = MetaClassSpecs::B.new
+    b_meta = MetaClassSpecs.metaclass_of b
+    b_meta_meta = MetaClassSpecs.metaclass_of b_meta
+    b_meta_meta.send(:define_method, :cheese) {'gouda'}
+    b_meta.cheese.should == 'gouda'
+
+    b_meta_meta_meta = MetaClassSpecs.metaclass_of b_meta_meta
+    b_meta_meta_meta.send(:define_method, :cheese) {'wensleydale'}
+    b_meta_meta.cheese.should == 'wensleydale'
+  end
+
+  it "calls a method defined on the metaclass of the metaclass" do
+    d_meta = MetaClassSpecs::D.singleton_class
+    d_meta.ham.should == 'iberico'
+  end
+end