Symfony\Component\Process\Process::checkTimeout PHP Method

    public function checkTimeout()
    {
        if ($this->status !== self::STATUS_STARTED) {
            return;
        }
        if (null !== $this->timeout && $this->timeout < microtime(true) - $this->starttime) {
            $this->stop(0);
            throw new ProcessTimedOutException($this, ProcessTimedOutException::TYPE_GENERAL);
        }
        if (null !== $this->idleTimeout && $this->idleTimeout < microtime(true) - $this->lastOutputTime) {
            $this->stop(0);
            throw new ProcessTimedOutException($this, ProcessTimedOutException::TYPE_IDLE);
        }
    }

 /**
  * Check if process is not running longer then specified timeout, return error message if so.
  * @param Process $process Process instance
  * @param string $testClass Name of tested class
  * @return string|null Error message if process timeout exceeded
  */
 protected function checkProcessTimeout(Process $process, $testClass)
 {
     try {
         $process->checkTimeout();
     } catch (ProcessTimedOutException $e) {
         return sprintf('[%s]: Process for class "%s" exceeded the time out of %d seconds and was killed.', date("Y-m-d H:i:s"), $testClass, $e->getExceededTimeout());
     }
 }