[Django]-How to connect Celery worker to django test database

You are regarding your test database as an ordinary database. So I think the best solution would be to define your test database as the default database under DATABASES settings in a separate settings file. And when running your worker you can pass the specific new settings file to your worker like this:

export DJANGO_SETTINGS_MODULE='[python path to your celery specific settings file]'
# the command to run your celery worker