Detect django testing mode

Question

I'm writing a reusable django app and I need to ensure that its models are only sync'ed when the app is in test mode. I've tried to use a custom DjangoTestRunner, but I found no examples of how to do that (the documentation only shows how to define a custom test runner).

So, does anybody have an idea of how to do it?

EDIT

Here's how I'm doing it:

#in settings.py
import sys
TEST = 'test' in sys.argv

Hope it helps.

Answer 1

The selected answer is a massive hack. :)

A less-massive hack would be to create your own TestSuiteRunner subclass and change a setting or do whatever else you need to for the rest of your application. You specify the test runner in your settings:

TEST_RUNNER = 'your.project.MyTestSuiteRunner'

In general, you don't want to do this, but it works if you absolutely need it.

from django.conf import settings
from django.test.simple import DjangoTestSuiteRunner

class MyTestSuiteRunner(DjangoTestSuiteRunner):
    def __init__(self, *args, **kwargs):
        settings.IM_IN_TEST_MODE = True
        super(MyTestSuiteRunner, self).__init__(*args, **kwargs)

NOTE: As of Django 1.8, DjangoTestSuiteRunner has been deprecated. You should use DiscoverRunner instead:

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


class MyTestSuiteRunner(DiscoverRunner):
    def __init__(self, *args, **kwargs):
        settings.IM_IN_TEST_MODE = True
        super(MyTestSuiteRunner, self).__init__(*args, **kwargs)

Answer 2

Not quite sure about your use case but one way I've seen to detect when the test suite is running is to check if django.core.mail has a outbox attribute such as:

from django.core import mail

if hasattr(mail, 'outbox'):
    # We are in test mode!
    pass
else:
    # Not in test mode...
    pass

This attributed is added by the Django test runner in setup_test_environment and removed in teardown_test_environment. You can check the source here: https://code.djangoproject.com/browser/django/trunk/django/test/utils.py

Edit: If you want models defined for testing only then you should check out Django ticket #7835 in particular comment #24 part of which is given below:

Apparently you can simply define models directly in your tests.py. Syncdb never imports tests.py, so those models won't get synced to the normal db, but they will get synced to the test database, and can be used in tests.

Answer 3

I'm using settings.py overrides. I have a global settings.py, which contains most stuff, and then I have overrides for it. Each settings file starts with:

from myproject.settings import settings

and then goes on to override some of the settings.

• prod_settings.py - Production settings (e.g. overrides DEBUG=False)
• dev_settings.py - Development settings (e.g. more logging)
• test_settings.py

And then I can define UNIT_TESTS=False in the base settings.py, and override it to UNIT_TESTS=True in test_settings.py.

Then whenever I run a command, I need to decide which settings to run against (e.g. DJANGO_SETTINGS_MODULE=myproject.test_settings ./manage.py test). I like that clarity.

Answer 4

Well, you can just simply use environment variables in this way:

export MYAPP_TEST=1 && python manage.py test

then in your settings.py file:

import os

TEST = os.environ.get('MYAPP_TEST')

if TEST:
    # Do something

Answer 5

I've been using Django class based settings. I use the 'switcher' from the package and load a different config/class for testing=True:

switcher.register(TestingSettings, testing=True)

In my configuration, I have a BaseSettings, ProductionSettings, DevelopmentSettings, TestingSettings, etc. They subclass off of each other as needed. In BaseSettings I have IS_TESTING=False, and then in TestingSettings I set it to True.

It works well if you keep your class inheritance clean. But I find it works better than the import * method Django developers usually use.

Answer 6

Although there are lots of good answers on this page, I think there is also another way to check if your project is in the test mode or not (if in some cases you couldn't use sys.argv[1:2] == ["test"]).

As you all may know DATABASE name will change to something like "test_*" (DATABASE default name will be prefixed with test) when you are in the test mode (or you can simply print it out to find your database name when you are running tests). Since I used pytest in one of my projects, I couldn't use

sys.argv[1:2] == ["test"]

because this argument wasn't there. So I simply used this one as my shortcut to check if I'm in the test environment or not (you know that your DATABASE name prefixed with test and if not just change test to your prefixed part of DATABASE name):

1) Any places other than settings module

from django.conf import settings

TESTING_MODE = "test" in settings.DATABASES["default"]["NAME"]

2) Inside the settings module

TESTING_MODE = "test" in DATABASES["default"]["NAME"]

or

TESTING_MODE = DATABASES["default"]["NAME"].startswith("test")  # for more strict checks

And if this solution is doable, you don't even need to import sys for checking this mode inside your settings.py module.