TST verify return none inplace in tests/indexing

pandas/tests/frame/test_constructors.py

@@ -1208,8 +1208,10 @@ def test_constructor_single_row(self):
         data = [OrderedDict([["a", 1.5], ["b", 3], ["c", 4], ["d", 6]])]
 
         result = DataFrame(data)
-        expected = DataFrame.from_dict(dict(zip([0], data)), orient="index")
-        tm.assert_frame_equal(result, expected.reindex(result.index))
+        expected = DataFrame.from_dict(dict(zip([0], data)), orient="index").reindex(
+            result.index
+        )
+        tm.assert_frame_equal(result, expected)
 
     def test_constructor_ordered_dict_preserve_order(self):
         # see gh-13304

pandas/tests/indexing/multiindex/test_indexing_slow.py

@@ -34,12 +34,15 @@ def validate(mi, df, key):
                 right = df[mask].copy()
 
                 if i + 1 != len(key):  # partial key
-                    right.drop(cols[: i + 1], axis=1, inplace=True)
-                    right.set_index(cols[i + 1 : -1], inplace=True)
+                    return_value = right.drop(cols[: i + 1], axis=1, inplace=True)
+                    assert return_value is None
+                    return_value = right.set_index(cols[i + 1 : -1], inplace=True)
+                    assert return_value is None
                     tm.assert_frame_equal(mi.loc[key[: i + 1]], right)
 
                 else:  # full key
-                    right.set_index(cols[:-1], inplace=True)
+                    return_value = right.set_index(cols[:-1], inplace=True)
+                    assert return_value is None
                     if len(right) == 1:  # single hit
                         right = Series(
                             right["jolia"].values, name=right.index[0], index=["jolia"]

pandas/tests/indexing/multiindex/test_ix.py

@@ -35,7 +35,8 @@ def test_loc_general(self):
             tm.assert_frame_equal(df.loc[key], df.iloc[2:])
 
         # this is ok
-        df.sort_index(inplace=True)
+        return_value = df.sort_index(inplace=True)
+        assert return_value is None
         res = df.loc[key]
 
         # col has float dtype, result should be Float64Index

pandas/tests/indexing/multiindex/test_sorted.py

@@ -43,8 +43,10 @@ def test_frame_getitem_not_sorted2(self, key):
         df2 = df.set_index(["col1", "col2"])
         df2_original = df2.copy()
 
-        df2.index.set_levels(["b", "d", "a"], level="col1", inplace=True)
-        df2.index.set_codes([0, 1, 0, 2], level="col1", inplace=True)
+        return_value = df2.index.set_levels(["b", "d", "a"], level="col1", inplace=True)
+        assert return_value is None
+        return_value = df2.index.set_codes([0, 1, 0, 2], level="col1", inplace=True)
+        assert return_value is None
         assert not df2.index.is_lexsorted()
         assert not df2.index.is_monotonic
 

pandas/tests/indexing/multiindex/test_xs.py

@@ -237,9 +237,11 @@ def test_series_getitem_multiindex_xs_by_label():
         [("a", "one"), ("a", "two"), ("b", "one"), ("b", "two")]
     )
     s = Series([1, 2, 3, 4], index=idx)
-    s.index.set_names(["L1", "L2"], inplace=True)
+    return_value = s.index.set_names(["L1", "L2"], inplace=True)
+    assert return_value is None
     expected = Series([1, 3], index=["a", "b"])
-    expected.index.set_names(["L1"], inplace=True)
+    return_value = expected.index.set_names(["L1"], inplace=True)
+    assert return_value is None
 
     result = s.xs("one", level="L2")
     tm.assert_series_equal(result, expected)