django-override-settings

django-override-settings provides an easy way to override settings in Django tests.

The override_settings class can be used as either a class/method decorator or as a context manager to temporarily override the values of settings. It works by creating a mock django.conf.settings object with user-defined attributes. After each test has finished or the context manager has exited, it resets the values in django.conf.settings so each test can run in its own sandbox without side-effects creeping in.

This package also provides two convenience functions (with_apps and without_apps) to modify just INSTALLED_APPS as well as a special object (SETTING_DELETED) to run tests without a given setting defined.

The functionality in this package will eventually be superseded when Django 1.4 is released as it will come with a built-in override_settings. But for those maintaining pre-1.4 codebases, hopefully this package comes in handy.

Installation

We're on PyPI:

pip install django-override-settings

Usage

If you have a bunch of tests that require a given setting, you can decorate the class and each test case will use that value. For example:

from django.conf import settings
from django.test import TestCase
from override_settings import override_settings

@override_settings(FOO="abc")
class TestFoo(TestCase):
    def test_foo(self):
        self.assertEqual(settings.FOO, "abc")

Or you can decorate a single test case and have it only apply on that method:

@override_settings(BAR="123")
class TestBar(TestCase):

    @override_settings(BAR="abc")
    def test_bar(self):
        self.assertEqual(settings.BAR, "abc")

    def test_bar_no_decoration(self):
        self.assertEqual(settings.BAR, "123")

You can also use it as a context manager:

class TestBar(TestCase):
    @override_settings(BAR="123")
    def test_bar(self):
        self.assertEqual(settings.BAR, "123")

        with override_settings(BAR="abc")
            self.assertEqual(settings.BAR, "abc")

        self.assertEqual(settings.BAR, "123")

To modify just INSTALLED_APPS, use with_apps or without_apps:

from override_settings import with_apps, without_apps

class TestAppModifiers(TestCase):
    @with_apps('django.contrib.humanize')
    def test_humanize(self):
        # ...

    @without_apps('django.contrib.sites')
    def test_no_sites(self):
        # ...

To run tests without a setting, use SETTING_DELETED:

from override_settings import override_settings, SETTING_DELETED

class TestMissingSetting(TestCase):
    @override_settings(CUSTOM_OPTION=SETTING_DELETED)
    def test_delete_custom_option(self):
        """
        Useful to make sure a missing setting raises an Exception.
        """
        self.assertRaises(AttributeError, getattr, settings, 'CUSTOM_OPTION')

Requirements

Works on Python versions 2.6 and 2.7 and with Django 1.2 through 1.4.

To run the test suite, you'll need tox (>= 1.4.2)

Thanks

Jannis Leidel for both the original snippet and his work updating it to work when decorating TestCases as part of Django proper.
Joost Cassee for the idea of SETTING_DELETED as well as with_apps and without_apps as part of his django-analytical project.

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