fixes

Author: topper-123

doc/source/whatsnew/v2.1.0.rst

@@ -24,7 +24,7 @@ In previous versions of pandas, the results of DataFrame reductions
 were of extension dtypes. Pandas can now keep the dtypes when doing reductions over Dataframe
 columns with a common dtype (:issue:`52788`).
 
-*New Behavior*
+*Old Behavior*
 
 .. code-block:: ipython
 

pandas/tests/reshape/merge/test_merge.py

@@ -2805,20 +2805,7 @@ def test_merge_datetime_different_resolution(tz, how):
 
 
 def test_merge_multiindex_single_level():
-    # GH #52331
-    df = DataFrame({"col": ["A", "B"]})
-    df2 = DataFrame(
-        data={"b": [100]},
-        index=MultiIndex.from_tuples([("A",), ("C",)], names=["col"]),
-    )
-    expected = DataFrame({"col": ["A", "B"], "b": [100, np.nan]})
-
-    result = df.merge(df2, left_on=["col"], right_index=True, how="left")
-    tm.assert_frame_equal(result, expected)
-
-
-def test_merge_multiindex_single_level():
-    # GH #52331
+    # GH52331
     df = DataFrame({"col": ["A", "B"]})
     df2 = DataFrame(
         data={"b": [100]},