exclude base classes from testing

Author: jbrockmendel

pandas/tests/tseries/test_offsets.py

@@ -4924,7 +4924,7 @@ def test_all_offset_classes(self):
 tick_classes = [x for x in offset_classes if issubclass(x, offsets.Tick)]
 
 
-@pytest.mark.parametrize('cls', month_classes+tick_classes)
+@pytest.mark.parametrize('cls', month_classes + tick_classes)
 @pytest.mark.parametrize('kwd', _rd_kwds)
 def test_valid_attributes(kwd, cls):
     # check that we cannot create e.g. MonthEnd(weeks=3)