We do use the pytest-django plugin to manage the django db setup magic,
so with this change, we can run tests without an existing db, or starting
a postgres db dedicated to the tests using pifpaf.
related to T1261
also:
- replace assertEquals -> assertEqual
- qdd a tox file
We need to explicitely specify the location where pytest looks for tests to prevent the kind of nasty error described here:
https://tox.readthedocs.io/en/latest/example/pytest.html#known-issues-and-limitations
Also note that migrations scripts are excluded from flake8 in the tox file.
related to T1247.