Options are:

- Implement a way for the test runner to ask test modules if they can be included for a certain db, possibly via a default app config? This would be specific to our test suite but require changes in `django.apps`.
- Put *everything* in `if` statements
- Make all the models have `managed=True` if the connection is incorrect (this might not work, it's just an idea)
- The current hack
- Your ideas here...