exclude base classes from testing

Author: jbrockmendel

pandas/tests/tseries/test_offsets.py

@@ -44,7 +44,11 @@
 
 offset_classes = [getattr(offsets, x) for x in dir(offsets)]
 offset_classes = [x for x in offset_classes if inspect.isclass(x) and
-                  issubclass(x, DateOffset)]
+                  issubclass(x, DateOffset) and
+                  x not in [offsets.YearOffset, offsets.Tick,
+                            offsets.SingleConstructorOffset,
+                            offsets.SemiMonthOffset,
+                            offsets.QuarterOffset, offsets.MonthOffset]]
 
 
 @pytest.fixture(params=offset_classes)

pandas/tseries/offsets.py

@@ -1686,6 +1686,8 @@ def __init__(self, n=1, normalize=False, startingMonth=None):
         self.startingMonth = startingMonth
 
         self.kwds = {'startingMonth': startingMonth}
+        self._offset = timedelta(1)
+        self._use_relativedelta = False
 
     def isAnchored(self):
         return (self.n == 1 and self.startingMonth is not None)