Counting business days between 2 dates

gistfile1.py

import unittest
from datetime import datetime, timedelta


def business_days(start, end):
    """
    Calculating business days between two dates excluding weekends

    :param start: First date
    :param end: Second date
    :rtype: integer
    """

    days = (end - start).days
    (full_weeks, remaining_days) = divmod(days, 7)
    business_days_count = full_weeks * 5
    
    if not remaining_days:
        return business_days_count

    full_weeks_dt = start + timedelta(days=full_weeks * 7)
    max_weekday = full_weeks_dt.isoweekday() + remaining_days
    
    if max_weekday > 7:
        remaining_days -= 2
    elif max_weekday > 6:
        remaining_days -= 1

    return business_days_count + remaining_days


class BusinessDaysTest(unittest.TestCase):
    def test_full_weeks(self):
        dates_results = (
            (datetime(2012, 7, 9), datetime(2012, 7, 16), 5),
            (datetime(2012, 7, 3), datetime(2012, 7, 24), 15),
        )
        for date1, date2, expected in dates_results:
            self.assertEqual(business_days(date1, date2), expected)

    def test_partial_Weeks(self):
        dates_results = (
            (datetime(2012, 7, 9), datetime(2012, 7, 14), 5),
            (datetime(2012, 7, 3), datetime(2012, 7, 20), 13),
            (datetime(2012, 6, 25), datetime(2012, 7, 11), 12),
        )
        for date1, date2, expected in dates_results:
            self.assertEqual(business_days(date1, date2), expected)


if __name__ == '__main__':
        unittest.main()
virhilo@sl500:~$ python buisness_timedelta.py 
..
----------------------------------------------------------------------
Ran 2 tests in 0.000s

OK