gistfile1.txt

# Create a method on a class that will duplicate an instance, 
# remove a method given as an argument and return the new methodless object

require 'test/unit'

module MetaClassFetcher
  def metaclass
    class <<self
      self
    end
  end
end

class MyClass
  def stripping(method_name)
    other = self.dup
    
    other.extend(MetaClassFetcher)
    other.metaclass.send(:undef_method,method_name.to_sym)

    return other
  end

  def clothes
    "undies"
  end
end

class ThingyTest < Test::Unit::TestCase
  def setup
    @receiver = MyClass.new
    @stripped = @receiver.stripping("clothes")
  end

  def test_stripping_will_duplicate_the_receiving_object
    assert @stripped.kind_of?(MyClass) && (@stripped.object_id != @receiver.object_id)
  end

  def test_stripping_will_not_return_nil
    assert !@stripped.nil?
  end

  def test_stripping_leaves_method_on_receiver 
    assert @receiver.respond_to?(:clothes)    
  end

  def test_stripping_can_remove_clothes
    assert !@stripped.respond_to?(:clothes)
  end

  def test_stripping_does_not_affect_newly_created_instances
    new_instance = MyClass.new
    assert new_instance.respond_to?(:clothes)
  end
end