RestContext::theResponseShouldContain PHP Method

    public function theResponseShouldContain($str)
    {
        if (!$this->responseIsJson) {
            if (strpos($this->responseData, $str) === false) {
                throw new \Exception(sprintf('String "%s" not found.', $str));
            }
        } else {
            throw new \Exception('Response should not be a JSON message.');
        }
    }