Make tests more robust, use django-pytest

tests/test_toast_middleware.py

@@ -1,10 +1,4 @@
 import json
-import os
-import django
-
-os.environ.setdefault("DJANGO_SETTINGS_MODULE", "timetracker.settings")
-django.setup()
-
 from django.contrib.messages import constants as message_constants
 from django.contrib.messages.storage.fallback import FallbackStorage
 from django.http import HttpRequest, HttpResponse