Unit Testing

Testing with Django

The first problem you’ll run in to when trying to write a test that runs a task is that Django’s test runner doesn’t use the same database as your celery daemon is using. If you’re using the database backend, this means that your tombstones won’t show up in your test database and you won’t be able to get the return value or check the status of your tasks.

There are two ways to get around this. You can either take advantage of CELERY_ALWAYS_EAGER = True to skip the daemon, or you can avoid testing anything that needs to check the status or result of a task.

Using a custom test runner to test with celery

If you’re going the CELERY_ALWAYS_EAGER route, which is probably better than just never testing some parts of your app, a custom Django test runner does the trick. Celery provides a simple test runner, but it’s easy enough to roll your own if you have other things that need to be done. http://docs.djangoproject.com/en/dev/topics/testing/#defining-a-test-runner

For this example, we’ll use the djcelery.contrib.test_runner to test the add task from the User Guide: Tasks examples in the Celery documentation.

To enable the test runner, set the following settings:

TEST_RUNNER = 'djcelery.contrib.test_runner.CeleryTestSuiteRunner'

Then we can put the tests in a tests.py somewhere:

from django.test import TestCase
from myapp.tasks import add

class AddTestCase(TestCase):

    def testNoError(self):
        """Test that the ``add`` task runs with no errors,
        and returns the correct result."""
        result = add.delay(8, 8)

        self.assertEquals(result.get(), 16)
        self.assertTrue(result.successful())

This test assumes that you put your example add task in maypp.tasks so adjust the import for wherever you put the class.