Neos\Flow\Persistence\Generic\PersistenceManager::add PHP Method

    public function add($object)
    {
        $this->hasUnpersistedChanges = true;
        $this->addedObjects->attach($object);
        $this->removedObjects->detach($object);
    }

 /**
  * @test
  */
 public function removeRemovesTheRightObjectEvenIfItHasBeenModifiedSinceItsAddition()
 {
     $object1 = new \ArrayObject(['val' => '1']);
     $object2 = new \ArrayObject(['val' => '2']);
     $object3 = new \ArrayObject(['val' => '3']);
     $persistenceManager = new Generic\PersistenceManager();
     $persistenceManager->add($object1);
     $persistenceManager->add($object2);
     $persistenceManager->add($object3);
     $object2['foo'] = 'bar';
     $object3['val'] = '2';
     $persistenceManager->remove($object2);
     $this->assertAttributeContains($object1, 'addedObjects', $persistenceManager);
     $this->assertAttributeNotContains($object2, 'addedObjects', $persistenceManager);
     $this->assertAttributeContains($object3, 'addedObjects', $persistenceManager);
 }