datetime_custom_rollover.py

datetime_custom_rollover.py

from datetime import datetime, time, date, timedelta

def rollover(dt: datetime, rollover: time) -> date:
	given_time = dt.time()
	if given_time < rollover:
		return dt.date()
	else:
		return dt.date() + timedelta(days=1)

def test_rollover():
	rollover_time = time(13, 0)

	# before 13:00 it's the given day
	assert rollover(datetime(2021, 1, 1, 0, 0), rollover_time) == date(2021, 1, 1)
	assert rollover(datetime(2021, 1, 1, 6, 0), rollover_time) == date(2021, 1, 1)
	assert rollover(datetime(2021, 1, 1, 12, 0), rollover_time) == date(2021, 1, 1)

	# after 13:00 it's the next day
	assert rollover(datetime(2021, 1, 1, 13, 0), rollover_time) == date(2021, 1, 2)
	assert rollover(datetime(2021, 1, 1, 16, 0), rollover_time) == date(2021, 1, 2)
	assert rollover(datetime(2021, 1, 1, 20, 0), rollover_time) == date(2021, 1, 2)
	assert rollover(datetime(2021, 1, 1, 23, 0), rollover_time) == date(2021, 1, 2)
	assert rollover(datetime(2021, 1, 1, 23, 59), rollover_time) == date(2021, 1, 2)

	# and it continues to be the next day until 13:00
	assert rollover(datetime(2021, 1, 2, 0, 0), rollover_time) == date(2021, 1, 2)
	assert rollover(datetime(2021, 1, 2, 6, 0), rollover_time) == date(2021, 1, 2)
	assert rollover(datetime(2021, 1, 2, 12, 0), rollover_time) == date(2021, 1, 2)

	# then it's the day after
	assert rollover(datetime(2021, 1, 2, 13, 0), rollover_time) == date(2021, 1, 3)