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require File.expand_path('../../spec_helper', __FILE__)
class AliasObject
attr :foo
attr_reader :bar
attr_accessor :baz
def prep; @foo = 3; @bar = 4; end
def value; 5; end
def false_value; 6; end
end
describe "The alias keyword" do
before(:each) do
@obj = AliasObject.new
@meta = class << @obj;self;end
end
it "creates a new name for an existing method" do
@meta.class_eval do
alias __value value
end
@obj.__value.should == 5
end
it "adds the new method to the list of methods" do
original_methods = @obj.methods
@meta.class_eval do
alias __value value
end
(@obj.methods - original_methods).map {|m| m.to_s }.should == ["__value"]
end
it "adds the new method to the list of public methods" do
original_methods = @obj.public_methods
@meta.class_eval do
alias __value value
end
(@obj.public_methods - original_methods).map {|m| m.to_s }.should == ["__value"]
end
it "overwrites an existing method with the target name" do
@meta.class_eval do
alias false_value value
end
@obj.false_value.should == 5
end
it "is reversible" do
@meta.class_eval do
alias __value value
alias value false_value
end
@obj.value.should == 6
@meta.class_eval do
alias value __value
end
@obj.value.should == 5
end
it "operates on the object's metaclass when used in instance_eval" do
@obj.instance_eval do
alias __value value
end
@obj.__value.should == 5
lambda { AliasObject.new.__value }.should raise_error(NoMethodError)
end
it "operates on methods defined via attr, attr_reader, and attr_accessor" do
@obj.prep
@obj.instance_eval do
alias afoo foo
alias abar bar
alias abaz baz
end
@obj.afoo.should == 3
@obj.abar.should == 4
@obj.baz = 5
@obj.abaz.should == 5
end
it "operates on methods with splat arguments" do
class AliasObject2;end
AliasObject2.class_eval do
def test(*args)
4
end
def test_with_check(*args)
test_without_check(*args)
end
alias test_without_check test
alias test test_with_check
end
AliasObject2.new.test(1,2,3,4,5).should == 4
end
it "operates on methods with splat arguments on eigenclasses" do
@meta.class_eval do
def test(*args)
4
end
def test_with_check(*args)
test_without_check(*args)
end
alias test_without_check test
alias test test_with_check
end
@obj.test(1,2,3,4,5).should == 4
end
it "operates on methods with splat arguments defined in a superclass" do
class AliasObject3;end
class Sub3 < AliasObject3;end
AliasObject3.class_eval do
def test(*args)
4
end
def test_with_check(*args)
test_without_check(*args)
end
end
Sub3.class_eval do
alias test_without_check test
alias test test_with_check
end
Sub3.new.test(1,2,3,4,5).should == 4
end
it "operates on methods with splat arguments defined in a superclass using text block for class eval" do
class Sub < AliasObject;end
AliasObject.class_eval <<-code
def test(*args)
4
end
def test_with_check(*args)
test_without_check(*args)
end
alias test_without_check test
alias test test_with_check
code
Sub.new.test("testing").should == 4
end
it "is not allowed against Fixnum or String instances" do
lambda do
1.instance_eval do
alias :foo :to_s
end
end.should raise_error(TypeError)
lambda do
:blah.instance_eval do
alias :foo :to_s
end
end.should raise_error(TypeError)
end
end
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