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Diffstat (limited to 'spec/ruby/language/alias_spec.rb')
| -rw-r--r-- | spec/ruby/language/alias_spec.rb | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/spec/ruby/language/alias_spec.rb b/spec/ruby/language/alias_spec.rb new file mode 100644 index 0000000000..e9f0050e17 --- /dev/null +++ b/spec/ruby/language/alias_spec.rb @@ -0,0 +1,246 @@ +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 + def self.klass_method; 7; 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 "works with a simple symbol on the left-hand side" do + @meta.class_eval do + alias :a value + end + @obj.a.should == 5 + end + + it "works with a single quoted symbol on the left-hand side" do + @meta.class_eval do + alias :'a' value + end + @obj.a.should == 5 + end + + it "works with a doubule quoted symbol on the left-hand side" do + @meta.class_eval do + alias :"a" value + end + @obj.a.should == 5 + end + + it "works with an interoplated symbol on the left-hand side" do + @meta.class_eval do + alias :"#{'a'}" value + end + @obj.a.should == 5 + end + + it "works with a simple symbol on the right-hand side" do + @meta.class_eval do + alias a :value + end + @obj.a.should == 5 + end + + it "works with a single quoted symbol on the right-hand side" do + @meta.class_eval do + alias a :'value' + end + @obj.a.should == 5 + end + + it "works with a doubule quoted symbol on the right-hand side" do + @meta.class_eval do + alias a :"value" + end + @obj.a.should == 5 + end + + it "works with an interoplated symbol on the right-hand side" do + @meta.class_eval do + alias a :"#{'value'}" + end + @obj.a.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 the class/module metaclass when used in instance_eval" do + AliasObject.instance_eval do + alias __klass_method klass_method + end + + AliasObject.__klass_method.should == 7 + lambda { Object.__klass_method }.should raise_error(NoMethodError) + end + + it "operates on the class/module metaclass when used in instance_exec" do + AliasObject.instance_exec do + alias __klass_method2 klass_method + end + + AliasObject.__klass_method2.should == 7 + lambda { Object.__klass_method2 }.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 + alias_class = Class.new + alias_class.class_eval do + def test(*args) + 4 + end + def test_with_check(*args) + test_without_check(*args) + end + end + sub = Class.new(alias_class) do + alias test_without_check test + alias test test_with_check + end + sub.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 + + it "on top level defines the alias on Object" do + # because it defines on the default definee / current module + ruby_exe("def foo; end; alias bla foo; print method(:bla).owner", escape: true).should == "Object" + end + + it "raises a NameError when passed a missing name" do + lambda { @meta.class_eval { alias undef_method not_exist } }.should raise_error(NameError) { |e| + # a NameError and not a NoMethodError + e.class.should == NameError + } + end +end |