updated whatsnew and test_groupby

Author: bobhaffner

doc/source/whatsnew/v0.21.1.txt

@@ -62,7 +62,7 @@ Bug Fixes
 - Bug in ``pd.Series.rolling.skew()`` and ``rolling.kurt()`` with all equal values has floating issue (:issue:`18044`)
 - Bug in ``pd.DataFrameGroupBy.count()`` when counting over a datetimelike column (:issue:`13393`)
 - Bug in ``pd.concat`` when empty and non-empty DataFrames or Series are concatenated (:issue:`18178` :issue:`18187`)
-- Bug in :class:`NDFrameGroupBy` fixes ValueError: no results error when grouping by a single column and aggregating with a tuple (:issue:`18079`)  
+- Bug when grouping by a single column and aggregating with a class like`list` or `tuple` (:issue:`18079`)  
 
 Conversion
 ^^^^^^^^^^

pandas/tests/groupby/test_groupby.py

@@ -2729,8 +2729,7 @@ def test_tuple_aggregation(self):
         assert_frame_equal(result, expected)
 
         result = df.groupby('A')['C'].aggregate(tuple)
-        expected = pd.Series([(1, 1, 1), (3, 4, 4)], index=[1, 3])
-        expected.name = 'C'
+        expected = pd.Series([(1, 1, 1), (3, 4, 4)], index=[1, 3], name='C')
         expected.index.name = 'A'
         assert_series_equal(result, expected)