Another shot at this problem ..

settings_test_snippet.py

class DisableMigrations(object):

    def __contains__(self, item):
        return True

    def __getitem__(self, item):
        return "notmigrations"

MIGRATION_MODULES = DisableMigrations()

If your Django version is >= 1.9

class DisableMigrations(object):
    def __contains__(self, item):
        return True

    def __getitem__(self, item):
        return None


MIGRATION_MODULES = DisableMigrations()

Awesome, thanks for this

This is available in Django 3.1 onwards as a setting https://docs.djangoproject.com/en/3.1/ref/settings/#migrate