Use “get” methods to help writing more testable code

Imagine you have the following code

def do_something():
    users = User.objects.filter(dob__gte='1980-01-01')
    for user in users:
        # do something to user

If you were writing unit test against do_something(), you would need to do some complex mocking on User.objects.filter() to return some mock up data.

But this can be easily prevented by refactoring into a separate get_users() method as below:

def get_users():
    return User.objects.filter(dob__gte='1980-01-01')

def do_something():
    users = get_users()
    for user in users:
        # do something to user

This way, you can just mock get_users() to return the mock data.