How to move embedded documents between parent documents in Doctrine ODM

MoveEmbeddedDocuments.php

<?php

namespace Doctrine\ODM\MongoDB\Tests\Functional;

use Doctrine\Common\Collections\ArrayCollection,
    Documents\Functional\EmbeddedTestLevel0,
    Documents\Functional\EmbeddedTestLevel1,
    Documents\Functional\EmbeddedTestLevel2;

class MoveEmbeddedDocuments extends \Doctrine\ODM\MongoDB\Tests\BaseTest
{
	
	public function testMoveEmbeddedDocuments()
	{
		$repo = $this->dm->getRepository(__NAMESPACE__.'\Category');
		$category1 = new Category;
		$category2 = new Category;
		
		$post1 = new Post('Post 1');
		$category1->addPost($post1);
		
		$this->dm->persist($category1);
		$this->dm->persist($category2);
		$this->dm->flush();
		
		$category1 = $repo->find($category1->getId());
		$category2 = $repo->find($category2->getId());
		$post = $category1->getPost('Post 1');
		$this->assertEquals('Post 1', $post->getTitle());
		
		$category1->movePostToCategory($post, $category2);
		
		$this->dm->flush();
		$this->dm->clear();
		$category1 = $repo->find($category1->getId());
		$category2 = $repo->find($category2->getId());
		
		$this->assertEquals(0, $category1->getPosts()->count());
		$this->assertEquals(1, $category2->getPosts()->count());
		
		$post = $category2->getPosts()->first();
		$this->assertInstanceOf(__NAMESPACE__.'\Post', $post);
		$this->assertEquals('Post 1', $post->getTitle());
	}
	
}

/** @Document */
class Category
{
	
	/** @Id */
	private $id;
	
	/** @EmbedMany(targetDocument="Post") */
	private $posts;
	
	public function __construct()
	{
		$this->posts = new ArrayCollection;
	}
	
	public function getId()
	{
		return $this->id;
	}
	
	public function addPost(Post $post)
	{
		$this->posts->add($post);
	}
	
	public function deletePost(Post $post)
	{
		$this->posts->removeElement($post);
	}
	
	public function movePostToCategory(Post $post, Category $category)
	{
		$category->addPost(clone $post);
		$this->deletePost($post);
	}
	
	public function getPost($name)
	{
		return $this->posts->filter(function($post) use($name){
			return $post->getTitle() === $name;
		})->first();
	}
	
	public function getPosts()
	{
		return $this->posts;
	}
	
}

/** @EmbeddedDocument */
class Post
{
	
	private $title;
	
	public function __construct($title)
	{
		$this->title = $title;
	}
	
	public function getTitle()
	{
		return $this->title;
	}
	
}