How to test celery periodic_task in Django?

Question

I have a simple periodic task:

from celery.decorators import periodic_task
from celery.task.schedules import crontab
from .models import Subscription

@periodic_task(run_every=crontab(minute=0, hour=0))
def deactivate_subscriptions():
    for subscription in Subscription.objects.filter(is_expired=True):
        print(subscription)
        subscription.is_active = False
        subscription.can_activate = False
        subscription.save()

And I want to cover it with tests.

I found information about how to test simple tasks, like @shared_task, but nowhere can I find an example of testing @periodic_task

Answer 1

When having a periodic task defined with a decorator you can access the crontab configuration the following way:

tasks.py

@periodic_task(
    run_every=(crontab(minute="*/1")),
)
def my_task():
    pass

some file where you need to access it

from .tasks import my_task

crontab = my_task.run_every

hours_when_it_will_run = crontab.hour
minutes_when_it_will_run = crontab.minute
day_of_the_week_when_it_will_run = crontab.day_of_week
day_of_the_month_when_it_will_run = crontab.day_of_month
month_of_year_when_it_will_run = crontab.month_of_year

This way you can access when task will be executed and you check in your test if the expected time is there.