Running celery task synchronous when testing django app

Celery support running task synchronous by config variable CELERY_ALWAYS_EAGER. But where to put this variable? and could I can select run celery task synchronous with some testcase?

I do some googling but did not find any good result. So I post this on my blog to help someone like me.

To set this variable in a testcase, just modify default django config variable at beginning of test case

# run celery task synchronous
from django.conf import settings
settings.CELERY_ALWAYS_EAGER = True

You can put this code in any testcase you want or in setUp function of a testcase.