👌 add copy=False to .rename_axis, use tm instead of pd.testing

Author: Marco Gorelli

pandas/core/frame.py

@@ -6767,7 +6767,7 @@ def append(self, other, ignore_index=False, verify_integrity=False, sort=False):
                 other.reindex(combined_columns, copy=False)
                 .to_frame()
                 .T.infer_objects()
-                .rename_axis(index.names)
+                .rename_axis(index.names, copy=False)
             )
             if not self.columns.equals(combined_columns):
                 self = self.reindex(columns=combined_columns)

pandas/tests/frame/test_combine_concat.py

@@ -297,7 +297,7 @@ def test_append_timestamps_aware_or_naive(self, tz_naive_fixture, timestamp):
         df = pd.DataFrame([pd.Timestamp(timestamp, tz=tz)])
         result = df.append(df.iloc[0]).iloc[-1]
         expected = pd.Series(pd.Timestamp(timestamp, tz=tz), name=0)
-        pd.testing.assert_series_equal(result, expected)
+        tm.assert_series_equal(result, expected)
 
     def test_update(self):
         df = DataFrame(