'Ensure that the MapField can be updated.'

def test_mapfield_update(self):

    class Member(EmbeddedDocument, ):
        gender = StringField()
        age = IntField()
    class Club(Document, ):
        members = MapField(EmbeddedDocumentField(Member))
    Club.drop_collection()
    club = Club()
    club.members['John'] = Member(gender='M', age=13)
    club.save()
    Club.objects().update(set__members={'John': Member(gender='F', age=14)})
    club = Club.objects().first()
    self.assertEqual(club.members['John'].gender, 'F')
    self.assertEqual(club.members['John'].age, 14)
