This TestSettingsManager class takes some of the pain out of making temporary changes to settings for the purposes of a unittest or doctest. It will keep track of the original settings and let you easily revert them back when you're done.
It also handles re-syncing the DB if you modify INSTALLED_APPS, which is especially handy if you have some test-only models in tests/models.py. This makes it easy to dynamically get those models synced to the DB before running your tests.
Sample doctest usage, for testing an app called "app_under_test," that has a tests/ sub-module containing a urls.py for testing URLs, a models.py with some testing models, and a templates/ directory with test templates:
>>> from test_utils import TestManager; mgr = TestManager()
>>> import os
>>> mgr.set(INSTALLED_APPS=('django.contrib.contenttypes',
... 'django.contrib.sessions',
... 'django.contrib.auth',
... 'app_under_test',
... 'app_under_test.tests'),
... ROOT_URLCONF='app_under_test.tests.urls',
... TEMPLATE_DIRS=(os.path.join(os.path.dirname(__file__),
... 'templates'),))
...do your doctests...
>>> mgr.revert()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | from django.conf import settings
from django.core.management import call_command
from django.db.models import loading
from django.test import TestCase
NO_SETTING = ('!', None)
class TestSettingsManager(object):
"""
A class which can modify some Django settings temporarily for a
test and then revert them to their original values later.
Automatically handles resyncing the DB if INSTALLED_APPS is
modified.
"""
def __init__(self):
self._original_settings = {}
def set(self, **kwargs):
for k,v in kwargs.iteritems():
self._original_settings.setdefault(k, getattr(settings, k,
NO_SETTING))
setattr(settings, k, v)
if 'INSTALLED_APPS' in kwargs:
self.syncdb()
def syncdb(self):
loading.cache.loaded = False
call_command('syncdb', verbosity=0)
def revert(self):
for k,v in self._original_settings.iteritems():
if v == NO_SETTING:
delattr(settings, k)
else:
setattr(settings, k, v)
if 'INSTALLED_APPS' in self._original_settings:
self.syncdb()
self._original_settings = {}
class SettingsTestCase(TestCase):
"""
A subclass of the Django TestCase with a settings_manager
attribute which is an instance of TestSettingsManager.
Comes with a tearDown() method that calls
self.settings_manager.revert().
"""
def __init__(self, *args, **kwargs):
super(SettingsTestCase, self).__init__(*args, **kwargs)
self.settings_manager = TestSettingsManager()
def tearDown(self):
self.settings_manager.revert()
|
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Comments
I kept having the feeling as I was writing this code that there MUST be some already-existing way to do this that I'm just too blind to see. Is there a better pattern for this that I'm missing?
#
What I do is define a new test_settings.py file that looks like:
Then copy your manage.py to manage_test.py and change the line: "import settings" to "import test_settings as settings"
run manage_test.py instead of manage.py whenever you want to use your test settings.
#
reanes's suggestion is great. Just remember to use
from django.conf import settings
rather than 'import settings' in your code that reads the settings, otherwise it'll just read the normal settings.py anyway.
#
Hmm, that solution doesn't seem like it would cover my use cases. I often have particular apps that need particular test settings (or additional test models), and it doesn't make sense to include those in the test settings for every single app.
#
@carljim: it complains that
ImproperlyConfigured: App with label testapp could not be found
when I modify INSTALLED_APPS (Django 1.1).syncdb
below seems to work:#
@carljim: I guess I was wrong,
syncdb
method was working just fine. But I had to subclassTransactionTestCase
in order to get tables for new models created.#
Really nice, very useful snippet! Thanks!
#
Note that the syncdb portion of this will only work in Django 1.1+ if you subclass from TransactionTestCase, which will slow your tests significantly. I don't really recommend the use of this snippet anymore.
#
Nice, thanks.
A note about NO_SETTING: setting it to something unlikely and then using == for comparison is less than ideal, because the unlikely value ('!', None) could be used in some remote setting.
A better approach is to create a new object for it, for example NO_SETTING = object(), and then using ≪is≫ for comparison. This is cleaner and safer, because Python will make sure no other value will ever evaluate true for ≪x is NO_SETTING≫.
#
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