[Django]-Unit testing with django-celery?

I like to use the override_settings decorator on tests which need celery results to complete.

from django.test import TestCase
from django.test.utils import override_settings
from myapp.tasks import mytask

class AddTestCase(TestCase):

    @override_settings(CELERY_EAGER_PROPAGATES_EXCEPTIONS=True,
                       CELERY_ALWAYS_EAGER=True,
                       BROKER_BACKEND='memory')
    def test_mytask(self):
        result = mytask.delay()
        self.assertTrue(result.successful())

If you want to apply this to all tests you can use the celery test runner as described at http://docs.celeryproject.org/en/2.5/django/unit-testing.html which basically sets these same settings except (BROKER_BACKEND = 'memory').

In settings:

TEST_RUNNER = 'djcelery.contrib.test_runner.CeleryTestSuiteRunner'

Look at the source for CeleryTestSuiteRunner and it’s pretty clear what’s happening.

Here’s an excerpt from my testing base class that stubs out the apply_async method and records to the calls to it (which includes Task.delay.) It’s a little gross, but it’s managed to fit my needs over the past few months I’ve been using it.

from django.test import TestCase
from celery.task.base import Task
# For recent versions, Task has been moved to celery.task.app:
# from celery.app.task import Task
# See http://docs.celeryproject.org/en/latest/reference/celery.app.task.html

class CeleryTestCaseBase(TestCase):

    def setUp(self):
        super(CeleryTestCaseBase, self).setUp()
        self.applied_tasks = []

        self.task_apply_async_orig = Task.apply_async

        @classmethod
        def new_apply_async(task_class, args=None, kwargs=None, **options):
            self.handle_apply_async(task_class, args, kwargs, **options)

        # monkey patch the regular apply_sync with our method
        Task.apply_async = new_apply_async

    def tearDown(self):
        super(CeleryTestCaseBase, self).tearDown()

        # Reset the monkey patch to the original method
        Task.apply_async = self.task_apply_async_orig

    def handle_apply_async(self, task_class, args=None, kwargs=None, **options):
        self.applied_tasks.append((task_class, tuple(args), kwargs))

    def assert_task_sent(self, task_class, *args, **kwargs):
        was_sent = any(task_class == task[0] and args == task[1] and kwargs == task[2]
                       for task in self.applied_tasks)
        self.assertTrue(was_sent, 'Task not called w/class %s and args %s' % (task_class, args))

    def assert_task_not_sent(self, task_class):
        was_sent = any(task_class == task[0] for task in self.applied_tasks)
        self.assertFalse(was_sent, 'Task was not expected to be called, but was.  Applied tasks: %s' %                 self.applied_tasks)

Here’s an “off the top of the head” example of how you’d use it in your test cases:

mymodule.py

from my_tasks import SomeTask

def run_some_task(should_run):
    if should_run:
        SomeTask.delay(1, some_kwarg=2)

test_mymodule.py

class RunSomeTaskTest(CeleryTestCaseBase):
    def test_should_run(self):
        run_some_task(should_run=True)
        self.assert_task_sent(SomeTask, 1, some_kwarg=2)

    def test_should_not_run(self):
        run_some_task(should_run=False)
        self.assert_task_not_sent(SomeTask)

since I still see this come up in search results, settings override with

TEST_RUNNER = 'djcelery.contrib.test_runner.CeleryTestSuiteRunner'

worked for me as per Celery Docs

This is what I did

Inside myapp.tasks.py I have:

from celery import shared_task

@shared_task()
def add(a, b):
    return a + b

Inside myapp.test_tasks.py I have:

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


class TasksTestCase(TestCase):

    def setUp(self):
        ...

    @override_settings(CELERY_TASK_ALWAYS_EAGER=True,CELERY_TASK_EAGER_PROPOGATES=True)
    def test_create_sections(self):
        result= add.delay(1,2)
        assert result.successful() == True
        assert result.get() == 3

For everyone getting here in 2019: checkout this article covering different strategies, including calling tasks synchronously.