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
Answers:
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.
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)))
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)
)
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.
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)
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)
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]}nn")
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"])
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
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.
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)))
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)
)
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.
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)
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)
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]}nn")
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"])