144 lines
3.5 KiB
Ruby
144 lines
3.5 KiB
Ruby
require_relative '../spec_helper'
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require_relative '../fixtures/class'
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require_relative 'fixtures/metaclass'
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describe "self in a metaclass body (class << obj)" do
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it "is TrueClass for true" do
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class << true; self; end.should == TrueClass
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end
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it "is FalseClass for false" do
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class << false; self; end.should == FalseClass
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end
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it "is NilClass for nil" do
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class << nil; self; end.should == NilClass
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end
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it "raises a TypeError for numbers" do
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lambda { class << 1; self; end }.should raise_error(TypeError)
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end
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it "raises a TypeError for symbols" do
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lambda { class << :symbol; self; end }.should raise_error(TypeError)
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end
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it "is a singleton Class instance" do
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cls = class << mock('x'); self; end
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cls.is_a?(Class).should == true
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cls.should_not equal(Object)
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end
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end
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describe "A constant on a metaclass" do
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before :each do
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@object = Object.new
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class << @object
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CONST = self
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end
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end
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it "can be accessed after the metaclass body is reopened" do
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class << @object
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CONST.should == self
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end
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end
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it "can be accessed via self::CONST" do
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class << @object
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self::CONST.should == self
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end
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end
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it "can be accessed via const_get" do
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class << @object
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const_get(:CONST).should == self
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end
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end
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it "is not defined on the object's class" do
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@object.class.const_defined?(:CONST).should be_false
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end
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it "is not defined in the metaclass opener's scope" do
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class << @object
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CONST
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end
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lambda { CONST }.should raise_error(NameError)
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end
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it "cannot be accessed via object::CONST" do
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lambda do
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@object::CONST
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end.should raise_error(TypeError)
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end
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it "raises a NameError for anonymous_module::CONST" do
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@object = Class.new
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class << @object
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CONST = 100
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end
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lambda do
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@object::CONST
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end.should raise_error(NameError)
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end
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it "appears in the metaclass constant list" do
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constants = class << @object; constants; end
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constants.should include(:CONST)
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end
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it "does not appear in the object's class constant list" do
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@object.class.constants.should_not include(:CONST)
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end
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it "is not preserved when the object is duped" do
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@object = @object.dup
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lambda do
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class << @object; CONST; end
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end.should raise_error(NameError)
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end
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it "is preserved when the object is cloned" do
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@object = @object.clone
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class << @object
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CONST.should_not be_nil
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end
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end
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end
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describe "calling methods on the metaclass" do
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it "calls a method on the metaclass" do
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MetaClassSpecs::A.cheese.should == 'edam'
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MetaClassSpecs::B.cheese.should == 'stilton'
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end
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it "calls a method on the instance's metaclass" do
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b = MetaClassSpecs::B.new
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b_meta = MetaClassSpecs.metaclass_of b
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b_meta.send(:define_method, :cheese) {'cheshire'}
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b.cheese.should == 'cheshire'
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end
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it "calls a method in deeper chains of metaclasses" do
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b = MetaClassSpecs::B.new
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b_meta = MetaClassSpecs.metaclass_of b
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b_meta_meta = MetaClassSpecs.metaclass_of b_meta
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b_meta_meta.send(:define_method, :cheese) {'gouda'}
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b_meta.cheese.should == 'gouda'
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b_meta_meta_meta = MetaClassSpecs.metaclass_of b_meta_meta
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b_meta_meta_meta.send(:define_method, :cheese) {'wensleydale'}
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b_meta_meta.cheese.should == 'wensleydale'
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end
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it "calls a method defined on the metaclass of the metaclass" do
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d_meta = MetaClassSpecs::D.singleton_class
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d_meta.ham.should == 'iberico'
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end
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end
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