RuntimeWarning when running the test suite on a new project

[Aymeric Augustin]

(reported on IRC)

19-21:33:09      carljm mYk: is there already an open ticket about the fact that when you start a new project and run its tests, you get RuntimeWarnings about timezones?
19-22:17:43      carljm mYk: it's in the contrib.auth tests
19-22:17:48      carljm three occurrences
19-22:17:57      carljm haven't tracked it down to the specific tests yet
19-22:18:10      carljm reproduction is just "startproject, configure db, manage.py test auth"
19-22:22:07       cramm carljm, mYk: /manage.py test -v2 auth.AuthContextProcessorTests.test_message_attrs auth.AuthViewNamedURLTests.test_named_urls auth.LoadDataWithNaturalKeysTestCase.test_user_is_created_and_added_to_group
19-22:22:28       cramm these are the three tests to run to reproduce what Carl reports

(reported in the comments of #17275)

I'm just switching our codebase to 1.4c2 and have run into this issue in the test suites.

To make sure it wasn't something I was doing, I did the following:

$ django-admin.py startproject blank 
$ cd blank/blank
$ <edit settings.py and set DB ENGINE to 'django.db.backends.sqlite3'
$ django-admin.py test 

Creating test database for alias 'default'...
..../home/slacy/src/oswebsite/wsve/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py:808: RuntimeWarning: DateTimeField received a naive datetime (2007-05-30 13:20:10) while time zone support is active.
  RuntimeWarning)
...../home/slacy/src/oswebsite/wsve/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py:808: RuntimeWarning: DateTimeField received a naive datetime (2006-12-17 07:03:31) while time zone support is active.
  RuntimeWarning)
........................../home/slacy/src/oswebsite/wsve/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py:808: RuntimeWarning: DateTimeField received a naive datetime (2012-01-13 00:14:00) while time zone support is active.
  RuntimeWarning)
...............................................................................................................................................................................................................................................................................................................s.......................................................................
----------------------------------------------------------------------
Ran 410 tests in 10.039s

OK (skipped=1)
Destroying test database for alias 'default'...

[Aymeric Augustin]

FYI the easiest way to debug this is to turn warning into exceptions as explained in ​the docs.

[Aymeric Augustin]

The root cause of the problem lies in the fixtures used by the tests of django.contrib.auth. As explained in ​the docs (once again!) it isn't possible to write fixtures that work both with and without USE_TZ.

The easiest solution is to override_settings(USE_TZ=False) in all tests that use fixtures.

---

This problem only affects contrib apps, whose tests are likely to be run with non-default settings.

A quick find shows that auth, flatpages and gis use fixtures and may suffer from the problem:

% find django -name .svn -prune -o -path \*/fixtures/\* -type f -print
django/contrib/auth/fixtures/authtestdata.json
django/contrib/auth/fixtures/context-processors-users.xml
django/contrib/auth/fixtures/natural.json
django/contrib/auth/fixtures/regular.json
django/contrib/flatpages/fixtures/sample_flatpages.json
django/contrib/gis/tests/distapp/fixtures/initial_data.json.gz
django/contrib/gis/tests/geoapp/fixtures/initial_data.json.gz
django/contrib/gis/tests/geogapp/fixtures/initial_data.json
django/contrib/gis/tests/relatedapp/fixtures/initial_data.json.gz

Upon closer inspection, only the auth fixtures contain serialized datetime objects, so the fix only needs to be applied to auth.

[Aymeric Augustin]

In [17770]:

Fixed #17940 -- Enforced USE_TZ = False in contrib apps tests that use fixtures containing datetimes.

[Steve Lacy]

This bug fix has introduced another bug #17966 which is in 1.4 final. Sigh. :)