public function testChromeUserAgent()
 {
     $this->stringContains('(KHTML, like Gecko) Chrome/', UserAgent::chrome());
 }
 /**
  * @param string $url
  *
  * @return string|null
  */
 protected function getUserAgent($url)
 {
     if (!$this->randomizeUserAgent) {
         return null;
     }
     return UserAgent::userAgent();
 }