def METHOD_NAME(self):
    # make all submissions public before test
    Submission.objects.filter(is_public=False).update(is_public=True)
    queryset = Submission.objects.filter(is_public=True)
    self.app_admin.make_submission_private(request, queryset)
    self.assertEqual(Submission.objects.filter(is_public=False).count(), 1)