Python parsedatetime library: enforce current year

natural_date.py

#
# Natural Language Date Parsing
# http://stackoverflow.com/q/25089784/1093087
#

import parsedatetime as pdt
from datetime import datetime, date, timedelta
from time import mktime
import pdb


def natural_date(human_readable):
    human_readable = human_readable.lower()

    # Flag to cause parsedatetime to never go forward
    # http://stackoverflow.com/a/25098991/1093087
    ptc = pdt.Constants()
    ptc.YearParseStyle = 0
    cal = pdt.Calendar(ptc)

    result, parsed_as = cal.parse(human_readable)

    if not parsed_as:
        raise ValueError("Unable to parse %s" % (human_readable))

    return date.fromtimestamp(mktime(result))


def test_natural_date():
    cases = [
        # input, expect
        ('jan 1', date(date.today().year, 1, 1)),
        ('dec 31', date(date.today().year, 12, 31)),
        ('yesterday', date.today() - timedelta(days=1)),
        ('3 months before 12/31', date(date.today().year, 9, 30))
    ]

    for human_readable, expect in cases:
        result = natural_date(human_readable)
        print("%s -> %s" % (human_readable, result))
        assert result == expect, human_readable


test_natural_date()
pdb.set_trace()