class RSpec::Mocks::MessageExpectation

def to_s
  args_description = error_generator.method_call_args_description(@argument_list_matcher.expected_args, "", "") { true }
  args_description = "(#{args_description})" unless args_description.start_with?("(")
  "#<#{self.class} #{error_generator.intro}.#{message}#{args_description}>"
end