MongoEngine/mongoengine — pull request #317 by wojcikstefan (2013-05-14 04:44:07+00:00)
Title: Querying a reference to a custom pk document is broken

This test fails on `self.assertEqual(B.objects.get(a=a.id).a, a)` with `InvalidId: custom_id is not a valid ObjectId`. It used to pass in previous versions of MongoEngine.