/**
  * Controls cloning of the object manager. Cloning should only be used within unit tests.
  *
  * @return void
  * @author Robert Lemke <*****@*****.**>
  */
 public function __clone()
 {
     $this->singletonObjectsRegistry = clone $this->singletonObjectsRegistry;
     $this->objectFactory = clone $this->objectFactory;
     $this->objectFactory->injectObjectManager($this);
 }