Override Django cache settings in tests

Question

I'm using Django DummyCache in my tests, however, there are a few tests which relay on real caching so using fake caching is not good here.

Is there a clean way to override the general Django settings for a certain module or scope? Preferably using a Python decorator.

I'm using Django version 1.8.4.

Answer 1

Take a look at https://docs.djangoproject.com/en/1.8/topics/testing/tools/#overriding-settings You can use decorator override_settings

from django.test import TestCase, override_settings

class MyTestCase(TestCase):

    @override_settings(CACHES=...)
    def test_something(self):
        ....

Answer 2

Yes, it is possible to override a setting. From Django documentation: Testing:

For testing purposes it’s often useful to change a setting temporarily and revert to the original value after running the testing code. For this use case Django provides a standard Python context manager ... settings(), which can be used like this:

from django.test import TestCase

class LoginTestCase(TestCase):
    def test_login(self):
        # Override the LOGIN_URL setting
        with self.settings(CACHES={'default': {'BACKEND': 'django.core.cache.backends.dummy.DummyCache'}}):
            response = self.client.get(...)

I have tested the above approach with several other settings myself, but not with the particular cache setting, but this is the general idea.

EDIT (credits @Alasdair):

Regrading the particular setting override, the following warning can be found in the documentation:

Altering the CACHESsetting is possible, but a bit tricky if you are using internals that make using of caching, like django.contrib.sessions. For example, you will have to reinitialize the session backend in a test that uses cached sessions and overrides CACHES.

Answer 3

If you are using pytest, you could put this fixture in your conftest.py file

from django.core.cache import cache

@pytest.fixture(autouse=True, scope="function")
def reset_cache():
    """
    Fixture to reset the cache after each test
    """
    yield
    cache.clear()