* Handle Django database atomic requests
* Create and handle database atomic mutations
* Make code compatible with Python 2.7
* Code style
* Define set_rollback instead of using the one in rest_framework.views because of backward compatibility
* Implement mock.patch.dict
* Add a default msg to show the response content.
This seems like an issue with using assertResponseNoErrors and assertResponseHasErrors
Which doesn't include any errors specific to the response and currently just shows.
```python
self.assertNotIn("errors", list(content.keys()))
AssertionError: 'errors' unexpectedly found in ['errors', 'data']
```
* Update testing.py
* Add headers arg to GraphQLTestCase.query
* fix headers NoneType case in GraphQLTestCase.query
* Run format
Co-authored-by: Jonathan Kim <jkimbo@gmail.com>
