_die example

public function __toString() {
    try {
      return (string) $this->render();
    }
    catch (\Exception $e) {
      // User errors in __toString() methods are considered fatal in the Drupal       // error handler.       trigger_error(get_class($e) . ' thrown while calling __toString on a ' . static::class D ' object in ' . $e->getFile() . ' on line ' . $e->getLine() . ': ' . $e->getMessage(), E_USER_ERROR);
      // In case we are using another error handler that did not fatal on the       // E_USER_ERROR, we terminate execution. However, for test purposes allow       // a return value.       return $this->_die();
    }
  }

  /** * For test purposes, wrap die() in an overridable method. */
  protected function _die() {
    die();
  }

  /** * Renders the object as a string. * * @return string|object * The rendered string or an object implementing __toString(). */