id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
17801	Adding DummyCache causes contrib.session tests to fail	Dougal Matthews	nobody	"Tested against Django trunk this morning. Create a new project, set the database engine and add this to the settings;

{{{
CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.dummy.DummyCache',
    },
}
}}}

Then run manage.py test and you should see this;


{{{
Creating test database for alias 'default'...
....................................................................................................................................F..........................F.....................................................................................................................................................................................................F......................................
======================================================================
FAIL: test_exists_searches_cache_first (django.contrib.sessions.tests.CacheDBSessionTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File ""/home/vagrant/.virtualenvs/mgp/lib/python2.6/site-packages/django/contrib/sessions/tests.py"", line 299, in test_exists_searches_cache_first
    self.assertTrue(self.session.exists(self.session.session_key))
  File ""/home/vagrant/.virtualenvs/mgp/lib/python2.6/site-packages/django/test/testcases.py"", line 274, in __exit__
    executed, self.num
AssertionError: 1 != 0 : 1 queries executed, 0 expected

======================================================================
FAIL: test_exists_searches_cache_first (django.contrib.sessions.tests.CacheDBSessionTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File ""/home/vagrant/.virtualenvs/mgp/lib/python2.6/site-packages/django/contrib/sessions/tests.py"", line 299, in test_exists_searches_cache_first
    self.assertTrue(self.session.exists(self.session.session_key))
  File ""/home/vagrant/.virtualenvs/mgp/lib/python2.6/site-packages/django/test/testcases.py"", line 274, in __exit__
    executed, self.num
AssertionError: 1 != 0 : 1 queries executed, 0 expected

======================================================================
FAIL: test_save (django.contrib.sessions.tests.CacheSessionTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File ""/home/vagrant/.virtualenvs/mgp/lib/python2.6/site-packages/django/contrib/sessions/tests.py"", line 136, in test_save
    self.assertTrue(self.session.exists(self.session.session_key))
AssertionError: False is not True

----------------------------------------------------------------------
Ran 396 tests in 15.930s

FAILED (failures=3)
Destroying test database for alias 'default'...
}}}

These make sense that they fail, but its not clear why from looking at the tracebacks. I guess the error should be clearer or they should be skipped?

Also, it seems strange, but one of the tests appears to have run and failed twice?"	Bug	closed	Core (Cache system)	1.4-beta-1	Normal	wontfix			Unreviewed	0	0	0	0	0	0