'If a complex field is set to the same value, it should not
be marked as changed.'

def test_complex_field_same_value_not_changed(self):

    class Simple(Document, ):
        mapping = ListField()
    Simple.drop_collection()
    e = Simple().save()
    e.mapping = []
    self.assertEqual([], e._changed_fields)
    class Simple(Document, ):
        mapping = DictField()
    Simple.drop_collection()
    e = Simple().save()
    e.mapping = {}
    self.assertEqual([], e._changed_fields)
