Format a timedelta into the largest possible unit (weeks is the largest in this case)

format_timedelta.py

def format_timedelta(td):
    """formats a timedelta into the largest unit possible

    >>> from datetime import timedelta
    >>> format_timedelta(timedelta(weeks=2))
    '2w'
    >>> format_timedelta(timedelta(weeks=2, minutes=2))
    '20162m'
    >>> format_timedelta(timedelta(days=2))
    '2d'
    >>> format_timedelta(timedelta(days=2, hours=2))
    '50h'
    >>> format_timedelta(timedelta(days=2, hours=2, minutes=1))
    '3001m'
    >>> format_timedelta(timedelta(hours=36))
    '36h'
    >>> format_timedelta(timedelta(hours=24))
    '1d'
    >>> format_timedelta(timedelta(hours=16))
    '16h'
    >>> format_timedelta(timedelta(hours=1))
    '1h'
    >>> format_timedelta(timedelta(minutes=120))
    '2h'
    >>> format_timedelta(timedelta(minutes=90))
    '90m'
    >>> format_timedelta(timedelta(minutes=59))
    '59m'
    >>> format_timedelta(timedelta(minutes=30))
    '30m'
    >>> format_timedelta(timedelta(minutes=1))
    '1m'
    >>> format_timedelta(timedelta(seconds=90))
    '90s'
    >>> format_timedelta(timedelta(seconds=59))
    '59s'
    >>> format_timedelta(timedelta(seconds=1))
    '1s'
    >>> format_timedelta(timedelta(milliseconds=2000))
    '2s'
    >>> format_timedelta(timedelta(milliseconds=999))
    '999ms'
    >>> format_timedelta(timedelta(milliseconds=1))
    '1ms'
    >>> format_timedelta(timedelta(microseconds=2000))
    '2ms'
    >>> format_timedelta(timedelta(microseconds=2500))
    '2500us'
    >>> format_timedelta(timedelta(microseconds=999))
    '999us'
    >>> format_timedelta(timedelta(microseconds=1))
    '1us'
    """
    total_seconds = td.total_seconds()
    units = [(604800, 'w'), (86400, 'd'), (3600, 'h'), (60, 'm'), (1, 's')]
    for seconds, unit in units:
        if total_seconds >= seconds and total_seconds % seconds == 0:
            return "%r%s" % (int(total_seconds / seconds), unit)
    if total_seconds >= 0.001:
        if (total_seconds / 0.001) % 1 == 0:
            return "%r%s" % (int(total_seconds * 1000), 'ms')
        else:
            micro = int(total_seconds / 0.000001)
            micro += int(total_seconds % 0.000001)
            return "%r%s" % (micro, 'us')
    return "%r%s" % (int(total_seconds * 1000000), 'us')

if __name__ == '__main__':
    import doctest
    doctest.testmod()