function it_normalizes_a_price_into_mongodb_document($mongoFactory, ProductPrice $price, \MongoId $mongoId)
 {
     $mongoFactory->createMongoId()->willReturn($mongoId);
     $price->getCurrency()->willReturn('USD');
     $price->getData()->willReturn(9.99);
     $this->normalize($price, 'mongodb_document')->shouldReturn(['_id' => $mongoId, 'currency' => 'USD', 'data' => 9.99]);
 }