remove_method_spec.rb

require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)

module ModuleSpecs
  class NoInheritance
    def method_to_remove; 1; end

    remove_method :method_to_remove
  end

  class Parent
    def method_to_remove; 1; end
  end

  class Child < Parent
    def method_to_remove; 2; end

    remove_method :method_to_remove
  end

  class First
    def method_to_remove; 1; end
  end

  class Second < First
    def method_to_remove; 2; end
  end
end

describe "Module#remove_method" do
  it "removes the method from a class" do
    x = ModuleSpecs::NoInheritance.new
    x.respond_to?(:method_to_remove).should == false
  end

  it "removes method from subclass, but not parent" do
    x = ModuleSpecs::Child.new
    x.respond_to?(:method_to_remove).should == true
    x.method_to_remove.should == 1
  end

  it "raises a NameError when attempting to remove method further up the inheritance tree" do
    lambda {
      class Third < ModuleSpecs::Second
        remove_method :method_to_remove
      end
    }.should raise_error(NameError)
  end

  it "raises a NameError when attempting to remove a missing method" do
    lambda {
      class Third < ModuleSpecs::Second
        remove_method :blah
      end
    }.should raise_error(NameError)
  end

  ruby_version_is ""..."1.9" do
    it "raises TypeError when frozen" do
      c = Class.new { def method_to_remove; end }
      c.freeze
      lambda { c.send(:remove_method, :method_to_remove) }.should raise_error(TypeError)
    end
  end

  ruby_version_is "1.9" do
    it "raises RuntimeError when frozen" do
      c = Class.new { def method_to_remove; end }
      c.freeze
      lambda { c.send(:remove_method, :method_to_remove) }.should raise_error(RuntimeError)
    end
  end
end