public function assertResponseReasonPhraseIsNot($phrase) {
        $this->requireResponse();

        try {
            Assertion::notSame($phrase, $this->response->getReasonPhrase(), sprintf(
                'Did not expect response reason phrase "%s".',
                $phrase
            ));
        } catch (AssertionFailure $e) {
            throw new AssertionFailedException($e->getMessage());
        }
    }