public function persistAllPassesRemovedObjectsToBackend()
{
$entity2 = new Fixture\Model\Entity2();
$objectStorage = new \SplObjectStorage();
$objectStorage->attach($entity2);
$mockBackend = $this->createMock(Generic\Backend\BackendInterface::class);
$mockBackend->expects($this->once())->method('setDeletedEntities')->with($objectStorage);
$manager = new Generic\PersistenceManager();
$manager->injectBackend($mockBackend);
$manager->remove($entity2);
$manager->persistAll();
}