'Merge a dictionary into existing value'

@execute_count(3)
def test_map_update_updates(self):

    partition = uuid4()
    cluster = 1
    TestQueryUpdateModel.objects.create(partition=partition, cluster=cluster, text_map={'foo': '1', 'bar': '2'})
    TestQueryUpdateModel.objects(partition=partition, cluster=cluster).update(text_map__update={'bar': '3', 'baz': '4'})
    obj = TestQueryUpdateModel.objects.get(partition=partition, cluster=cluster)
    self.assertEqual(obj.text_map, {'foo': '1', 'bar': '3', 'baz': '4'})
