No need for mocking?

main.py

from datetime import date

END_OF_EARLY_BIRD = date(2020, 6, 1)


def calculate_price(current_day):
    # if today() > END_OF_EARLY_BIRD:
    # no more call to today() => easy to test => no mock necessary
    if current_day > END_OF_EARLY_BIRD:
        return 1000
    else:
        return 800


def main():
    # huh - but what about this one?
    price = calculate_price(current_day=date.today())
    print(f'You have to pay {price}')


if __name__ == '__main__':
    main()