'Ensure that asking for _data returns \'id\'.'

def test_data_contains_id_field(self):

    class Person(Document, ):
        name = StringField()
    Person.drop_collection()
    Person(name='Harry    Potter').save()
    person = Person.objects.first()
    self.assertTrue(('id' in person._data.keys()))
    self.assertEqual(person._data.get('id'), person.id)
