class ActiveSupport::Testing::SimpleStubs

def stub_object(object, method_name, return_value)
  key = [object.object_id, method_name]
  if stub = @stubs[key]
    unstub_object(stub)
  end
  new_name = "__simple_stub__#{method_name}"
  @stubs[key] = Stub.new(object, method_name, new_name)
  object.singleton_class.send :alias_method, new_name, method_name
  object.define_singleton_method(method_name) { return_value }
end