[Django]-How to Unit test with different settings in Django?

You can do anything you like to the UnitTest subclass, including setting and reading instance properties:

from django.conf import settings

class MyTest(unittest.TestCase):
   def setUp(self):
       self.old_setting = settings.NUM_LATEST
       settings.NUM_LATEST = 5 # value tested against in the TestCase

   def tearDown(self):
       settings.NUM_LATEST = self.old_setting

Since the django test cases run single-threaded, however, I’m curious about what else may be modifying the NUM_LATEST value? If that “something else” is triggered by your test routine, then I’m not sure any amount of monkey patching will save the test without invalidating the veracity of the tests itself.

You can pass --settings option when running tests

python manage.py test --settings=mysite.settings_local

Although overriding settings configuration on runtime might help, in my opinion you should create a separate file for testing. This saves lot of configuration for testing and this would ensure that you never end up doing something irreversible (like cleaning staging database).

Say your testing file exists in ‘my_project/test_settings.py’, add

settings = 'my_project.test_settings' if 'test' in sys.argv else 'my_project.settings'

in your manage.py. This will ensure that when you run python manage.py test you use test_settings only. If you are using some other testing client like pytest, you could as easily add this to pytest.ini

Update: the solution below is only needed on Django 1.3.x and earlier. For >1.4 see slinkp’s answer.

If you change settings frequently in your tests and use Python ≥2.5, this is also handy:

from contextlib import contextmanager

class SettingDoesNotExist:
    pass

@contextmanager
def patch_settings(**kwargs):
    from django.conf import settings
    old_settings = []
    for key, new_value in kwargs.items():
        old_value = getattr(settings, key, SettingDoesNotExist)
        old_settings.append((key, old_value))
        setattr(settings, key, new_value)
    yield
    for key, old_value in old_settings:
        if old_value is SettingDoesNotExist:
            delattr(settings, key)
        else:
            setattr(settings, key, old_value)

Then you can do:

with patch_settings(MY_SETTING='my value', OTHER_SETTING='other value'):
    do_my_tests()

You can override setting even for a single test function.

from django.test import TestCase, override_settings

class SomeTestCase(TestCase):

    @override_settings(SOME_SETTING="some_value")
    def test_some_function():
        

or you can override setting for each function in class.

@override_settings(SOME_SETTING="some_value")
class SomeTestCase(TestCase):

    def test_some_function():
        

For pytest users.

The biggest issue is:

• override_settings doesn’t work with pytest.
• Subclassing Django’s TestCase will make it work but then you can’t use pytest fixtures.

The solution is to use the settings fixture documented here.

Example

def test_with_specific_settings(settings):
    settings.DEBUG = False
    settings.MIDDLEWARE = []
    ..

And in case you need to update multiple fields

def override_settings(settings, kwargs):
    for k, v in kwargs.items():
        setattr(settings, k, v)


new_settings = dict(
    DEBUG=True,
    INSTALLED_APPS=[],
)


def test_with_specific_settings(settings):
    override_settings(settings, new_settings)

@override_settings is great if you don’t have many differences between your production and testing environment configurations.

In other case you’d better just have different settings files. In this case your project will look like this:

your_project
    your_app
        ...
    settings
        __init__.py
        base.py
        dev.py
        test.py
        production.py
    manage.py

So you need to have your most of your settings in base.py and then in other files you need to import all everything from there, and override some options. Here’s what your test.py file will look like:

from .base import *

DEBUG = False

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': 'app_db_test'
    }
}

PASSWORD_HASHERS = (
    'django.contrib.auth.hashers.MD5PasswordHasher',
)

LOGGING = {}

And then you either need to specify --settings option as in @MicroPyramid answer, or specify DJANGO_SETTINGS_MODULE environment variable and then you can run your tests:

export DJANGO_SETTINGS_MODULE=settings.test
python manage.py test 

I created a new settings_test.py file which would import everything from settings.py file and modify whatever is different for testing purpose.
In my case I wanted to use a different cloud storage bucket when testing.

settings_test.py:

from project1.settings import *
import os

CLOUD_STORAGE_BUCKET = 'bucket_name_for_testing'

manage.py:

def main():

    # use seperate settings.py for tests
    if 'test' in sys.argv:
        print('using settings_test.py')
        os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'project1.settings_test')
    else:
        os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'project1.settings')

    try:
        from django.core.management import execute_from_command_line
    except ImportError as exc:
        raise ImportError(
            "Couldn't import Django. Are you sure it's installed and "
            "available on your PYTHONPATH environment variable? Did you "
            "forget to activate a virtual environment?"
        ) from exc
    execute_from_command_line(sys.argv)

Found this while trying to fix some doctests… For completeness I want to mention that if you’re going to modify the settings when using doctests, you should do it before importing anything else…

>>> from django.conf import settings

>>> settings.SOME_SETTING = 20

>>> # Your other imports
>>> from django.core.paginator import Paginator
>>> # etc

I’m using pytest.

I managed to solve this the following way:

import django    
import app.setting
import modules.that.use.setting

# do some stuff with default setting
setting.VALUE = "some value"
django.setup()
import importlib
importlib.reload(app.settings)
importlib.reload(modules.that.use.setting)
# do some stuff with settings new value

You can override settings in test in this way:

from django.test import TestCase, override_settings

test_settings = override_settings(
    DEFAULT_FILE_STORAGE='django.core.files.storage.FileSystemStorage',
    PASSWORD_HASHERS=(
        'django.contrib.auth.hashers.UnsaltedMD5PasswordHasher',
    )
)


@test_settings
class SomeTestCase(TestCase):
    """Your test cases in this class"""

And if you need these same settings in another file you can just directly import test_settings.

If you have multiple test files placed in a subdirectory (python package), you can override settings for all these files based on condition of presence of ‘test’ string in sys.argv

app
  tests
    __init__.py
    test_forms.py
    test_models.py

__init__.py:

import sys
from project import settings

if 'test' in sys.argv:
    NEW_SETTINGS = {
        'setting_name': value,
        'another_setting_name': another_value
    }
    settings.__dict__.update(NEW_SETTINGS)

Not the best approach. Used it to change Celery broker from Redis to Memory.

One setting for all tests in a testCase

class TestSomthing(TestCase):
    def setUp(self, **kwargs):
        with self.settings(SETTING_BAR={ALLOW_FOO=True})
            yield

override one setting in the testCase

from django.test import override_settings

    @override_settings(SETTING_BAR={ALLOW_FOO=False})
    def i_need_other_setting(self):
        ...

Important

Even though you are overriding these settings this will not apply to settings that your server initialize stuff with because it is already initialized, to do that you will need to start django with another setting module.

I really like using a custom test runner (taken from @meshy’s answer over here), since:

• It doesn’t rely on command-line arguments (which could be forgotten).
• It doesn’t require modifying your actual test cases.

Put the following in myapp/test_runner.py:

from django.conf import settings
from django.test.runner import DiscoverRunner

class MyTestRunner(DiscoverRunner):
    def setup_test_environment(self):
        super().setup_test_environment()
        settings.NEWS_NUM_LATEST = 42
        # ...any other settings you want to override...

and the following in project/settings.py:

TEST_RUNNER = 'myapp.test_runner.MyTestRunner'

If you don’t want to use the override_settings decorator you can use this syntax

with override_settings(CUSTOMER_ORDERS_ALLOWED=0):
    # Test