Django single-test migration

I have recently implemented a reusable app within the django project I am working on. For the sake of the question, let's call it reusable_app. This app also has some unittests that run, however, these tests depend on some basic models declared somewhere next to the tests in a model.py.

Now, the the models aren't loaded in the database unless I specify the folder in INSTALLED_APPS in the testing configuration file. I was wondering if there is another way to achieve this, not having to expose the app in the settings file? I seem to be able to specify the app via @override_settings, but the migrations are not ran. Am I missing something?