def METHOD_NAME(self, backend):
    obj = models.UnindexedBook.objects.create(
        title="Test", publication_date=date(2017, 10, 18), number_of_pages=100
    )
    self.assertEqual(backend().add.call_count, 0)
    self.assertIsNone(backend().add.call_args)
    backend().reset_mock()
    obj.title = "Updated test"
    obj.save()
    self.assertEqual(backend().add.call_count, 0)
    self.assertIsNone(backend().add.call_args)