public function testSerializeObjectWithRelations()
{
$author = new Author();
$author->setFirstName('John');
$book = new Book();
$book->setTitle('Foo4');
$book->setISBN('1234');
$book->setAuthor($author);
$book->save();
$b = clone $book;
$sb = serialize($b);
$book->clearAllReferences();
$this->assertEquals($book, unserialize($sb));
}