/Languages/Ruby/Tests/mspec/rubyspec/language/metaclass_spec.rb

require File.dirname(__FILE__) + '/../spec_helper'
require File.dirname(__FILE__) + '/../fixtures/class'

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

  ruby_version_is ""..."1.9" do
    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
  end

  ruby_version_is "1.9" do
    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
  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