Another way to tackle this issue is to have the updated_at constant and change the two_days_ago.

I usually achieve this by making the current date a parameter, for example rewrite the notify function like this:

def check_pending_invoices(asof):
invoices = Invoice.objects.filter(
updated_at__lt=asof - datetime.timedelta(days=2),

Or better yet, remove the number of days from the function all together:

def check_pending_invoices(since):
invoices = Invoice.objects.filter(

Now the test can create a notification and test by changing the asof date:

def test_should_notify(self):
def test_should_not_notify(self):

I usually try to avoid importing timezone at low level modules and pass the “current time” from higher level modules such as API’s and management commands. Makes testing a lot easier.

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