How can I unit test django messages?

Question

In my django application, I'm trying to write a unit test that performs an action and then checks the messages in the response.

As far as I can tell, there is no nice way of doing this.

I'm using the CookieStorage storage method, and I'd like to do something similar to the following:

    response = self.client.post('/do-something/', follow=True)
    self.assertEquals(response.context['messages'][0], "fail.")

The problem is, all I get back is a

print response.context['messages']
<django.contrib.messages.storage.cookie.CookieStorage object at 0x3c55250>

How can I turn this into something useful, or am I doing it all wrong?

Thanks, Daniel

this works, but... seriously? response.context['messages']._get()[0][0].__dict__['message'] — dvydra, May 24 '10 at 14:16
You can try to encapsulate this not so beautiful code in beautiful function `assert_has_message(response, msg_text)` and use it everywhere you would like after that. If you'll find better way to access the messages, you'll just modify the function in one place. — nkrkv, May 24 '10 at 18:59
@nailxx, yeah, that's basically what I've done, but it's making me feel unwell :) — dvydra, May 24 '10 at 23:11
This also works: `messages_list = CookieStorage(response)._decode(response.cookies['messages'].value)` This gives you a list of django.contrib.messages.storage.base.Message objects. — dvydra, May 25 '10 at 09:58
@dvydra if you're still around, you may want to change the accepted answer — OrangeDog, May 04 '18 at 15:07

score 131 · Accepted Answer · edited May 04 '18 at 15:06

131

I found a really easy approach:

response = self.client.post('/foo/')
messages = list(response.context['messages'])
self.assertEqual(len(messages), 1)
self.assertEqual(str(messages[0]), 'my message')

If you need to check for messages on a response that has no context you can use the following:

from django.contrib.messages import get_messages
messages = list(get_messages(response.wsgi_request))
self.assertEqual(len(messages), 1)
self.assertEqual(str(messages[0]), 'my message')

The fallback storage doesn't support indexing, however it is an iterable.

edited May 04 '18 at 15:06

OrangeDog

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answered Feb 16 '13 at 11:26

daveoncode

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2

I also found that `self.assertEqual(m[0].message, 'my message')` works – Aaron Lelevier Aug 22 '14 at 14:12
6

if you need to check for messages on a response that has no context (such as a redirect), you can use `list(r.wsgi_request._messages)` – BenjaminGolder Jan 19 '17 at 11:10
8

It looks like [0] does not work on the new versions : `*** TypeError: 'FallbackStorage' object does not support indexing`. However, it is an Iterable and you can use any `for m in messages` construct. – Dunatotatos Mar 19 '17 at 11:06
Nice one @BenjaminGolder where did you find that? Digging into the source code? – Jonathan Jul 20 '17 at 12:50
2

@Jonathan by using `dir()` in inside an interactive debugger (`import ipdb; ipdb.set_trace()`) inside a test case. – BenjaminGolder Jul 25 '17 at 17:23
1

@Jonathan https://docs.djangoproject.com/en/2.0/_modules/django/contrib/messages/middleware – OrangeDog May 04 '18 at 13:00
The way to do it without touching private attributes is `get_messages(response.wsgi_request)` – OrangeDog May 04 '18 at 15:02
1

`messages = [str(message) for message in get_messages(post_response.wsgi_request)]` `self.assertListEqual(["some message."], messages)` may save a few chars – FiddleStix Feb 14 '20 at 13:56

score 30 · Answer 2 · edited Jul 08 '20 at 14:50

30

From django documentation:

Outside of templates, you can use get_messages()

So, you could write something like:

from django.contrib.messages import get_messages

[...]

messages = [m.message for m in get_messages(response.wsgi_request)]
self.assertIn('My message', messages)

edited Jul 08 '20 at 14:50

powlo

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answered Oct 21 '17 at 16:38

moppag

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anttikoo · Answer 3 · 2011-02-08T15:01:22.357

This works for me (displays all messages):

print [m.message for m in list(response.context['messages'])]

Also here are a couple of utility methods I have in a test class inherited from Django's TestCase. If you'd prefer to have them as functions, remove the self arguments and replace self.fail()'s with a raise.

def assert_message_count(self, response, expect_num):
    """
    Asserts that exactly the given number of messages have been sent.
    """

    actual_num = len(response.context['messages'])
    if actual_num != expect_num:
        self.fail('Message count was %d, expected %d' %
            (actual_num, expect_num))

def assert_message_contains(self, response, text, level=None):
    """
    Asserts that there is exactly one message containing the given text.
    """

    messages = response.context['messages']

    matches = [m for m in messages if text in m.message]

    if len(matches) == 1:
        msg = matches[0]
        if level is not None and msg.level != level:
            self.fail('There was one matching message but with different'
                'level: %s != %s' % (msg.level, level))

        return

    elif len(matches) == 0:
        messages_str = ", ".join('"%s"' % m for m in messages)
        self.fail('No message contained text "%s", messages were: %s' %
            (text, messages_str))
    else:
        self.fail('Multiple messages contained text "%s": %s' %
            (text, ", ".join(('"%s"' % m) for m in matches)))

def assert_message_not_contains(self, response, text):
    """ Assert that no message contains the given text. """

    messages = response.context['messages']

    matches = [m for m in messages if text in m.message]

    if len(matches) > 0:
        self.fail('Message(s) contained text "%s": %s' %
            (text, ", ".join(('"%s"' % m) for m in matches)))

Only works with explicit ResponseContext or TemplateResponse (which tries to construct a ResponseContext). — pkoch, Oct 24 '11 at 20:24

Manoj Govindan · Answer 4 · 2018-02-04T12:21:33.553

Update

My original answer was written when django was still 1.1 or so. This answer is no longer relevant. See @daveoncode's answer for a better solution.

Original Answer

I did an experiment to test this. I changed the MESSAGE_STORAGE setting in one of my projects to 'django.contrib.messages.storage.cookie.CookieStorage' and executed a test that I had written to check for messages. It worked.

The key difference from what you were doing is the way I retrieved messages. See below:

def test_message_sending(self):
    data = dict(...)
    response = self.client.post(reverse('my_view'), data)
    messages = self.user.get_and_delete_messages()

    self.assertTrue(messages)
    self.assertEqual('Hey there!', messages[0])

This may be worth a try.

user.get_and_delete_messages() was deprecated in Django 1.2 – Dave Nov 17 '11 at 00:14 — Dave, Nov 17 '11 at 00:14

score 1 · Answer 5 · answered May 18 '22 at 12:47

I created a python class to simplify messages testing :

class TestMessageCase(TestCase):
""" class inherited from TestCase to add a function to test messages response """

def assertMessageContains(self, response, messages_list, debug=False):
    """
    Function to test messages returned by the response view

    :param response: The response of the view
    :param messages_list: An ordered list of messages to test
    :type messages_list: list of string
    :param debug: Show all response messages
    :type debug: bool
    """

    response_messages = list(response.context['messages'])

    if debug:
        print(
            " ---------------------------------------------------------------------\n",
            "|              DEBUG MESSAGES RETURNED BY THE RESPONSE              |\n",
            "---------------------------------------------------------------------"
        )
        for i in range(len(response_messages)):
            print(f"Message n°{i + 1} :\n{response_messages[i]}\n\n")
        print(
            " ---------------------------------------------------------------------\n",
            "|                             END DEBUG                             |\n",
            "---------------------------------------------------------------------"
        )

    self.assertEqual(len(response_messages), len(messages_list))
    for i in range(len(response_messages)):
        self.assertEqual(str(response_messages[i]), messages_list[i])

And in test function :

response = self.client.post('/foo/')
self.assertMessageContains(response, ["Foo"])

Marco Fucci · Answer 6 · 2012-05-11T16:02:44.910

Simpler version of the stalemate one:

class TestCaseMessagesMixture(object):
    def assertMessageCount(self, response, expect_num):
        """
        Asserts that exactly the given number of messages have been sent.
        """

        actual_num = len(response.context['messages'])
        if actual_num != expect_num:
            self.fail('Message count was %d, expected %d' %
                    (actual_num, expect_num)
                )

    def assertMessageEqual(self, response, text):
        """
        Asserts that the response includes the message text.
        """

        messages = [m.message for m in response.context['messages']]

        if text not in messages:
            self.fail(
                'No message with text "%s", messages were: %s' % 
                    (text, messages)
                )

    def assertMessageNotEqual(self, response, text):
        """
        Asserts that the response does not include the message text.
        """

        messages = [m.message for m in response.context['messages']]

        if text in messages:
            self.fail(
                'Message with text "%s" found, messages were: %s' % 
                    (text, messages)
                )

This is not exactly the same, as my version checks that the given text is _contained_ in (not _equal_ to) any/none of the messages. I prefer it that way, so that I only have to enter the key part of the message in a testcase and allow the message text to be updated without breaking the test. — anttikoo, Jun 11 '12 at 12:00

score 0 · Answer 7 · answered Jul 06 '20 at 18:44

Test helpers for validation of response messages count and content

def get_response_messages(self, response):
    from django.contrib.messages import get_messages
    return list(get_messages(response.wsgi_request))


def check_response_messages(self, response, message_index=None, message_value=None, exp_count=None):
    messages = self.get_response_messages(response)
    if exp_count is not None:
        self.assertEqual(len(messages), exp_count)

    if message_index is not None:
        message = messages[message_index]
        self.assertIn(message_value, str(message))

Can be used like this

message_value = "You can not switch to another type of account"
self.check_response_messages(response, exp_count=1, message_index=0, message_value=message_value)

How can I unit test django messages?

7 Answers7

Update

Original Answer

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