/**
* 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());
}
}