Django how to test if message is sent

Question

I want to test if message is sent to user after submit. I'm using django.contrib.messages. Everything seems to be working during manual testing (runserver), but in unit test I don't get messages.

Code that stores message:

messages.success(request, _('Internationalized evil message.'))

Code that should test message:

from django.contrib.messages.api import get_messages

...

def test_message_should_sent_to_user(self):
    """After successful phone number submit, message should be displayed."""
    response = self.client.post(
        reverse('evil.views.evil_data_submit'), self.valid_data)
    messages = get_messages(response.request)
    self.assertNotEqual(len(messages), 0)

It looks like that no middleware is called during test client post method call.

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Update after @Tisho answer

Messages should be found in response.context, even my guts say that it should work, but it doesn't. I've placed import pdb; pdb.set_trace() in django/contrib/messages/context_processors.py to see if its called during test client.post, its not.

I've double checked TEMPLATE_CONTEXT_PROCESSORS, MIDDLEWARE_CLASSES and INSTALLED_APPS - probably tomorrow I'll discover that I missed something.

---

Important detail

Forgot to mention that in case of successful submit view returns HttpResponseRedirect therefore response.context is empty.

---

Solution

View returns redirect (which has no context data), to solve that we can pass follow=True to client.post method (method suggested by @Tisho).

Answer 1

During unit tests, the message could be found in

response = self.client.post(
    reverse('evil.views.evil_data_submit'), self.valid_data)
messages = response.context['messages']

If your view returns a redirect, response.context will be empty unless you pass follow=True, like so:

response = self.client.post(
    reverse('evil.views.evil_data_submit'),
    self.valid_data,
    follow=True)

Answer 2

The best way I found is by using mock

http://www.voidspace.org.uk/python/mock/patch.html#patch-methods-start-and-stop

class SimpleCommentTestDirect(TestCase):

def setUp(self):
    self._patcher1 = patch('django.contrib.messages.error')
    self.mock_error = self._patcher1.start()

def tearDown(self):
    self._patcher1.stop()

def test_error_message(self):
    self.client.get('/vote/direct/unknownapp/comment/1/up/')
    self.assertEqual(self.mock_error.call_args[0][1], 'Wrong request. Model.')

BTW: There are also should be a way to get request by using mock. And by using request object get message from django.contrib.messages.get_messages