/**
  * Safety net around register_shutdown_function of Maintenance.php
  */
 public function __destruct()
 {
     if (!$this->shutdownSimulated && !$this->testCase->hasFailed()) {
         // Someone generated a MaintenanceFixup instance without calling
         // simulateShutdown. We'd have to raise a PHPUnit exception to correctly
         // flag this illegal usage. However, we are already in a destruktor, which
         // would trigger undefined behaviour. Hence, we can only report to the
         // error output :( Hopefully people read the PHPUnit output.
         fwrite(STDERR, "ERROR! Instance of " . __CLASS__ . " destructed without " . "calling simulateShutdown method. Call simulateShutdown on the " . "instance before it gets destructed.");
     }
     // The following guard is required, as PHP does not offer default destructors :(
     if (is_callable("parent::__destruct")) {
         parent::__destruct();
     }
 }