Merge pull request #49 from dateutil/relativedelta-enhancements

Relativedelta enhancements - inheritance and weeks property.

dateutil/relativedelta.py

@@ -167,7 +167,7 @@ def __init__(self, dt1=None, dt2=None,
         else:
             self.years = years
             self.months = months
-            self.days = days+weeks*7
+            self.days = days + weeks * 7
             self.leapdays = leapdays
             self.hours = hours
             self.minutes = minutes
@@ -242,6 +242,13 @@ def _fix(self):
         else:
             self._has_time = 0
 
+    @property
+    def weeks(self):
+        return self.days // 7
+    @weeks.setter
+    def weeks(self, value):
+        self.days = self.days - (self.weeks * 7) + value*7
+
     def _set_months(self, months):
         self.months = months
         if abs(self.months) > 11:
@@ -254,7 +261,7 @@ def _set_months(self, months):
 
     def __add__(self, other):
         if isinstance(other, relativedelta):
-            return relativedelta(years=other.years+self.years,
+            return self.__class__(years=other.years+self.years,
                                  months=other.months+self.months,
                                  days=other.days+self.days,
                                  hours=other.hours+self.hours,
@@ -323,7 +330,7 @@ def __rsub__(self, other):
     def __sub__(self, other):
         if not isinstance(other, relativedelta):
             raise TypeError("unsupported type for sub operation")
-        return relativedelta(years=self.years-other.years,
+        return self.__class__(years=self.years-other.years,
                              months=self.months-other.months,
                              days=self.days-other.days,
                              hours=self.hours-other.hours,
@@ -341,7 +348,7 @@ def __sub__(self, other):
                              microsecond=self.microsecond or other.microsecond)
 
     def __neg__(self):
-        return relativedelta(years=-self.years,
+        return self.__class__(years=-self.years,
                              months=-self.months,
                              days=-self.days,
                              hours=-self.hours,
@@ -380,7 +387,7 @@ def __bool__(self):
 
     def __mul__(self, other):
         f = float(other)
-        return relativedelta(years=int(self.years*f),
+        return self.__class__(years=int(self.years*f),
                              months=int(self.months*f),
                              days=int(self.days*f),
                              hours=int(self.hours*f),

dateutil/test/test.py

@@ -36,6 +36,33 @@ class RelativeDeltaTest(unittest.TestCase):
     now = datetime(2003, 9, 17, 20, 54, 47, 282310)
     today = date(2003, 9, 17)
 
+    def testInheritance(self):
+        # Ensure that relativedelta is inheritance-friendly.
+        class rdChildClass(relativedelta):
+            pass
+
+        ccRD = rdChildClass(years=1, months=1, days=1, leapdays=1, weeks=1,
+                            hours=1, minutes=1, seconds=1, microseconds=1)
+
+        rd = relativedelta(years=1, months=1, days=1, leapdays=1, weeks=1,
+                           hours=1, minutes=1, seconds=1, microseconds=1)
+
+        self.assertEqual(type(ccRD + rd), type(ccRD),
+                         msg='Addition does not inherit type.')
+
+        self.assertEqual(type(ccRD - rd), type(ccRD),
+                         msg='Subtraction does not inherit type.')
+
+        self.assertEqual(type(-ccRD), type(ccRD),
+                         msg='Negation does not inherit type.')
+
+        self.assertEqual(type(ccRD * 5.0), type(ccRD),
+                         msg='Multiplication does not inherit type.')
+
+        self.assertEqual(type(ccRD / 5.0), type(ccRD),
+                         msg='Division does not inherit type.')
+
+
     def testNextMonth(self):
         self.assertEqual(self.now+relativedelta(months=+1),
                          datetime(2003, 10, 17, 20, 54, 47, 282310))
@@ -197,6 +224,14 @@ def testBoolean(self):
         self.assertFalse(relativedelta(days=0))
         self.assertTrue(relativedelta(days=1))
 
+    def testWeeks(self):
+        # Test that the weeks property is working properly.
+        rd = relativedelta(years=4, months=2, weeks=8, days=6)
+        self.assertEqual((rd.weeks, rd.days), (8, 8 * 7 + 6))
+
+        rd.weeks = 3
+        self.assertEqual((rd.weeks, rd.days), (3, 3 * 7 + 6))
+
 
 class RRuleTest(unittest.TestCase):
     def testYearly(self):