whatsnew, gh references in tests

Author: jbrockmendel

doc/source/whatsnew/v0.23.0.txt

@@ -586,7 +586,7 @@ Datetimelike API Changes
 - Operations between a :class:`Series` with dtype ``dtype='datetime64[ns]'`` and a :class:`PeriodIndex` will correctly raises ``TypeError`` (:issue:`18850`)
 - Subtraction of :class:`Series` with timezone-aware ``dtype='datetime64[ns]'`` with mis-matched timezones will raise ``TypeError`` instead of ``ValueError`` (:issue:`18817`)
 - :func:`pandas.merge` provides a more informative error message when trying to merge on timezone-aware and timezone-naive columns (:issue:`15800`)
-- For :class:`DatetimeIndex` and :class:`TimedeltaIndex` with ``freq=None``, addition or subtraction of integer-dtyped array or ``Index`` will raise ``NullFrequencyError`` instead of ``TypeError`` (:issue:`19895`)
+- For :class:`DatetimeIndex` and :class:`TimedeltaIndex` with ``freq=None``, addition or subtraction of integer-dtyped array or ``Index`` will raise ``NullFrequencyError`` instead of ``TypeError`` if the index ``freq`` attribute is ``None``, and will return an object of the same class otherwise (:issue:`19895`, :issue:`19959`)
 
 .. _whatsnew_0230.api.other:
 

pandas/tests/indexes/datetimes/test_arithmetic.py

@@ -361,6 +361,7 @@ def test_dti_isub_int(self, tz, one):
     @pytest.mark.parametrize('freq', ['H', 'D'])
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_dti_add_intarray_tick(self, box, freq):
+        # GH#19959
         dti = pd.date_range('2016-01-01', periods=2, freq=freq)
         other = box([4, -1])
         expected = DatetimeIndex([dti[n] + other[n] for n in range(len(dti))])
@@ -372,6 +373,7 @@ def test_dti_add_intarray_tick(self, box, freq):
     @pytest.mark.parametrize('freq', ['W', 'M', 'MS', 'Q'])
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_dti_add_intarray_non_tick(self, box, freq):
+        # GH#19959
         dti = pd.date_range('2016-01-01', periods=2, freq=freq)
         other = box([4, -1])
         expected = DatetimeIndex([dti[n] + other[n] for n in range(len(dti))])
@@ -384,6 +386,7 @@ def test_dti_add_intarray_non_tick(self, box, freq):
 
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_dti_add_intarray_no_freq(self, box):
+        # GH#19959
         dti = pd.DatetimeIndex(['2016-01-01', 'NaT', '2017-04-05 06:07:08'])
         other = box([9, 4, -1])
         with pytest.raises(NullFrequencyError):

pandas/tests/indexes/period/test_arithmetic.py

@@ -443,6 +443,7 @@ def test_pi_sub_isub_offset(self):
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     @pytest.mark.parametrize('op', [operator.add, ops.radd])
     def test_pi_add_intarray(self, box, op):
+        # GH#19959
         pi = pd.PeriodIndex([pd.Period('2015Q1'), pd.Period('NaT')])
         other = box([4, -1])
         result = op(pi, other)
@@ -451,6 +452,7 @@ def test_pi_add_intarray(self, box, op):
 
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_pi_sub_intarray(self, box):
+        # GH#19959
         pi = pd.PeriodIndex([pd.Period('2015Q1'), pd.Period('NaT')])
         other = box([4, -1])
         result = pi - other

pandas/tests/indexes/timedeltas/test_arithmetic.py

@@ -535,6 +535,7 @@ def test_tdi_isub_int(self, one):
 
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_tdi_add_integer_array(self, box):
+        # GH#19959
         rng = timedelta_range('1 days 09:00:00', freq='H', periods=3)
         other = box([4, 3, 2])
         expected = TimedeltaIndex(['1 day 13:00:00'] * 3)
@@ -545,6 +546,7 @@ def test_tdi_add_integer_array(self, box):
 
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_tdi_sub_integer_array(self, box):
+        # GH#19959
         rng = timedelta_range('9H', freq='H', periods=3)
         other = box([4, 3, 2])
         expected = TimedeltaIndex(['5H', '7H', '9H'])
@@ -555,6 +557,7 @@ def test_tdi_sub_integer_array(self, box):
 
     @pytest.mark.parametrize('box', [np.array, pd.Index])
     def test_tdi_addsub_integer_array_no_freq(self, box):
+        # GH#19959
         tdi = TimedeltaIndex(['1 Day', 'NaT', '3 Hours'])
         other = box([14, -1, 16])
         with pytest.raises(NullFrequencyError):