text: from django.contrib import messages
  from django.test import RequestFactory, SimpleTestCase
  
  
  class DummyStorage:
      """
      dummy message-store to test the api methods
      """
  
      def __init__(self):
          self.store = []
  
      def add(self, level, message, extra_tags=""):
          self.store.append(message)
  
  
  class ApiTests(SimpleTestCase):
      rf = RequestFactory()
  
      def setUp(self):
          self.request = self.rf.request()
          self.storage = DummyStorage()
  
      def test_ok(self):
          msg = "some message"
          self.request._messages = self.storage
          messages.add_message(self.request, messages.DEBUG, msg)
          self.assertIn(msg, self.storage.store)
  
      def test_request_is_none(self):
          msg = "add_message() argument must be an HttpRequest object, not 'NoneType'."
          self.request._messages = self.storage
          with self.assertRaisesMessage(TypeError, msg):
              messages.add_message(None, messages.DEBUG, "some message")
          self.assertEqual(self.storage.store, [])
  
      def test_middleware_missing(self):
          msg = (
              "You cannot add messages without installing "
              "django.contrib.messages.middleware.MessageMiddleware"
          )
          with self.assertRaisesMessage(messages.MessageFailure, msg):
              messages.add_message(self.request, messages.DEBUG, "some message")
          self.assertEqual(self.storage.store, [])
  
      def test_middleware_missing_silently(self):
          messages.add_message(
              self.request, messages.DEBUG, "some message", fail_silently=True
          )
          self.assertEqual(self.storage.store, [])
  
  
  class CustomRequest:
      def __init__(self, request):
          self._request = request
  
      def __getattribute__(self, attr):
          try:
              return super().__getattribute__(attr)
          except AttributeError:
              return getattr(self._request, attr)
  
  
  class CustomRequestApiTests(ApiTests):
      """
      add_message() should use ducktyping to allow request wrappers such as the
      one in Django REST framework.
      """
  
      def setUp(self):
          super().setUp()
          self.request = CustomRequest(self.request)
  