Add function to convert a relative date to an absolute date.

RelativeDate.py

+from datetime import date, timedelta
+import re
+
+def _convert_pattern(p_length, p_period):
+    result = None
+
+    p_length = int(p_length)
+
+    if p_period == 'd':
+        result = date.today() + timedelta(p_length)
+    elif p_period == 'w':
+        result = date.today() + timedelta(weeks=p_length)
+    elif p_period == 'm':
+        # we'll consider a month to be 30 days
+        result = date.today() + timedelta(30 * p_length)
+    elif p_period == 'y':
+        # we'll consider a year to be 365 days (yeah, I'm aware of leap years)
+        result = date.today() + timedelta(365 * p_length)
+
+    return result
+
+def _convert_weekday_pattern(p_weekday):
+    day_value = {
+            'mo': 0,
+            'tu': 1,
+            'we': 2,
+            'th': 3,
+            'fr': 4,
+            'sa': 5,
+            'su': 6
+            }
+
+    targetDayString = p_weekday[:2].lower()
+    targetDay = day_value[targetDayString]
+
+    day = date.today().weekday()
+
+    shift = (targetDay - day) % 7
+    return date.today() + timedelta(shift)
+
+def relative_date_to_date(p_date):
+    """
+    Transforms a relative date into a date object.
+
+    The following formats are understood:
+
+    * [0-9][dwmy]
+    * 'today' or 'tomorrow'
+    * days of the week (in full or abbreviated)
+    """
+
+    result = None
+    p_date = p_date.lower()
+
+    relative = re.match('(?P<length>[0-9]+)(?P<period>[dwmy])$', p_date, re.I)
+    weekday = re.match('mo(n(day)?)?$|tu(e(sday)?)?$|we(d(nesday)?)?$|th(u(rsday)?)?$|fr(i(day)?)?$|sa(t(urday)?)?$|su(n(day)?)?$', p_date)
+
+    if relative:
+        length = relative.group('length')
+        period = relative.group('period')
+        result = _convert_pattern(length, period)
+
+    elif weekday:
+        result = _convert_weekday_pattern(weekday.group(0))
+
+    elif re.match('tod(ay)?$', p_date):
+        result = _convert_pattern('0', 'd')
+
+    elif re.match('tom(orrow)?$', p_date):
+        result = _convert_pattern('1', 'd')
+
+    return result

test/RelativeDateTest.py

+from datetime import date, timedelta
+import unittest
+
+import RelativeDate
+
+class RelativeDateTester(unittest.TestCase):
+    def setUp(self):
+        self.today = date.today()
+        self.tomorrow = self.today + timedelta(1)
+        self.monday = self.today + timedelta(7 - self.today.weekday() % 7)
+
+    def test_zero_days(self):
+        result = RelativeDate.relative_date_to_date('0d')
+        self.assertEquals(result, self.today)
+
+    def test_one_day(self):
+        result = RelativeDate.relative_date_to_date('1d')
+        self.assertEquals(result, self.tomorrow)
+
+    def test_one_week(self):
+        result = RelativeDate.relative_date_to_date('1w')
+        self.assertEquals(result, date.today() + timedelta(weeks=1))
+
+    def test_one_month(self):
+        result = RelativeDate.relative_date_to_date('1m')
+        self.assertEquals(result, date.today() + timedelta(30))
+
+    def test_one_year(self):
+        result = RelativeDate.relative_date_to_date('1y')
+        self.assertEquals(result, date.today() + timedelta(365))
+
+    def test_zero_months(self):
+        result = RelativeDate.relative_date_to_date('0m')
+        self.assertEquals(result, self.today)
+
+    def test_zero_years(self):
+        result = RelativeDate.relative_date_to_date('0y')
+        self.assertEquals(result, self.today)
+
+    def test_garbage1(self):
+        result = RelativeDate.relative_date_to_date('0dd')
+        self.assertFalse(result)
+
+    def test_garbage2(self):
+        result = RelativeDate.relative_date_to_date('-0d')
+        self.assertFalse(result)
+
+    def test_one_day_capital(self):
+        result = RelativeDate.relative_date_to_date('1D')
+        self.assertEquals(result, self.tomorrow)
+
+    def test_today1(self):
+        result = RelativeDate.relative_date_to_date('today')
+        self.assertEquals(result, self.today)
+
+    def test_today2(self):
+        result = RelativeDate.relative_date_to_date('tod')
+        self.assertEquals(result, self.today)
+
+    def test_tomorrow1(self):
+        result = RelativeDate.relative_date_to_date('Tomorrow')
+        self.assertEquals(result, self.tomorrow)
+
+    def test_tomorrow2(self):
+        result = RelativeDate.relative_date_to_date('tom')
+        self.assertEquals(result, self.tomorrow)
+
+    def test_monday1(self):
+        result = RelativeDate.relative_date_to_date('monday')
+        self.assertEquals(result, self.monday)
+
+    def test_monday2(self):
+        result = RelativeDate.relative_date_to_date('mo')
+        self.assertEquals(result, self.monday)
+
+    def test_monday3(self):
+        result = RelativeDate.relative_date_to_date('mon')
+        self.assertEquals(result, self.monday)
+
+    def test_monday4(self):
+        result = RelativeDate.relative_date_to_date('mondayy')
+        self.assertFalse(result)