gistfile1.php

$timeToFail = time() + $this->config['time_tolerance'];
$el = null;

while(!$this->timeToleranceReached($timeToFail) && !$el){
  $page = $this->session->getPage();
  $el = null;
  try {
      \Symfony\Component\CssSelector\CssSelector::toXPath($selector);
      $el = $page->find('css', $selector);
  } catch (\Symfony\Component\CssSelector\Exception\ParseException $e) {}
  
  try {
      if (!$el) $el = @$page->find('xpath',$selector);
  } catch (\Exception $e) {
  }
}
  
if (!$el) \PHPUnit_Framework_Assert::fail("CSS or XPath for '$selector' not found'");
return $el;