public function assertResponseBodyIs(PyStringNode $content) {
        $this->requireResponse();
        $content = (string) $content;

        try {
            Assertion::same($body = (string) $this->response->getBody(), $content, sprintf(
                'Expected response body "%s", got "%s".',
                $content,
                $body
            ));
        } catch (AssertionFailure $e) {
            throw new AssertionFailedException($e->getMessage());
        }
    }