public function testGetPrimaryKeyWithEntityWithCompositeKeys()
 {
     /** @var Book[] $books */
     $books = $this->em->getRepository($this->bookFullClassName)->findAll();
     foreach ($books as $book) {
         $values = EntityHelper::getPrimaryKeyValue($this->em, $book);
         $this->assertEquals($book->getId(), $values['id']);
         $this->assertEquals($book->getOwnerId(), $values['ownerId']);
     }
 }