Fix more tests

Author: mroeschke

pandas/core/groupby/groupby.py

@@ -5694,7 +5694,7 @@ def _insert_quantile_level(idx: Index, qs: npt.NDArray[np.float64]) -> MultiInde
         idx = cast(MultiIndex, idx)
         levels = list(idx.levels) + [lev]
         codes = [np.repeat(x, nqs) for x in idx.codes] + [np.tile(lev_codes, len(idx))]
-        mi = MultiIndex(levels=levels, codes=codes, names=idx.names + [None])
+        mi = MultiIndex(levels=levels, codes=codes, names=list(idx.names) + [None])
     else:
         nidx = len(idx)
         idx_codes = coerce_indexer_dtype(np.arange(nidx), idx)

pandas/core/reshape/melt.py

@@ -132,7 +132,7 @@ def melt(
         else:
             mdata[col] = np.tile(id_data._values, K)
 
-    mcolumns = id_vars + var_name + [value_name]
+    mcolumns = id_vars + list(var_name) + [value_name]
 
     if frame.shape[1] > 0:
         mdata[value_name] = concat(

pandas/core/reshape/pivot.py

@@ -395,7 +395,7 @@ def _all_key(key):
                 if isinstance(piece.index, MultiIndex):
                     # We are adding an empty level
                     transformed_piece.index = MultiIndex.from_tuples(
-                        [all_key], names=piece.index.names + [None]
+                        [all_key], names=list(piece.index.names) + [None]
                     )
                 else:
                     transformed_piece.index = Index([all_key], name=piece.index.name)

pandas/core/strings/accessor.py

@@ -3507,7 +3507,7 @@ def str_extractall(arr, pat, flags: int = 0) -> DataFrame:
 
     from pandas import MultiIndex
 
-    index = MultiIndex.from_tuples(index_list, names=arr.index.names + ["match"])
+    index = MultiIndex.from_tuples(index_list, names=list(arr.index.names) + ["match"])
     dtype = _result_dtype(arr)
 
     result = arr._constructor_expanddim(

pandas/tests/frame/methods/test_rename_axis.py

@@ -60,15 +60,15 @@ def test_rename_axis_mapper(self):
 
         # Test for renaming index using dict
         result = df.rename_axis(index={"ll": "foo"})
-        assert result.index.names == ["foo", "nn"]
+        assert result.index.names == ("foo", "nn")
 
         # Test for renaming index using a function
         result = df.rename_axis(index=str.upper, axis=0)
-        assert result.index.names == ["LL", "NN"]
+        assert result.index.names == ("LL", "NN")
 
         # Test for renaming index providing complete list
         result = df.rename_axis(index=["foo", "goo"])
-        assert result.index.names == ["foo", "goo"]
+        assert result.index.names == ("foo", "goo")
 
         # Test for changing index and columns at same time
         sdf = df.reset_index().set_index("nn").drop(columns=["ll", "y"])

pandas/tests/frame/methods/test_set_index.py

@@ -130,7 +130,7 @@ def test_set_index_names(self):
         df = tm.makeDataFrame()
         df.index.name = "name"
 
-        assert df.set_index(df.index).index.names == ["name"]
+        assert df.set_index(df.index).index.names == ("name",)
 
         mi = MultiIndex.from_arrays(df[["A", "B"]].T.values, names=["A", "B"])
         mi2 = MultiIndex.from_arrays(
@@ -139,7 +139,7 @@ def test_set_index_names(self):
 
         df = df.set_index(["A", "B"])
 
-        assert df.set_index(df.index).index.names == ["A", "B"]
+        assert df.set_index(df.index).index.names == ("A", "B")
 
         # Check that set_index isn't converting a MultiIndex into an Index
         assert isinstance(df.set_index(df.index).index, MultiIndex)
@@ -259,7 +259,7 @@ def test_set_index_pass_single_array(
             # only valid column keys are dropped
             # since B is always passed as array above, nothing is dropped
             expected = df.set_index(["B"], drop=False, append=append)
-            expected.index.names = [index_name] + name if append else name
+            expected.index.names = [index_name] + list(name) if append else name
 
             tm.assert_frame_equal(result, expected)
 
@@ -432,12 +432,12 @@ def test_set_index_datetime(self):
         df = df.set_index("label", append=True)
         tm.assert_index_equal(df.index.levels[0], expected)
         tm.assert_index_equal(df.index.levels[1], Index(["a", "b"], name="label"))
-        assert df.index.names == ["datetime", "label"]
+        assert df.index.names == ("datetime", "label")
 
         df = df.swaplevel(0, 1)
         tm.assert_index_equal(df.index.levels[0], Index(["a", "b"], name="label"))
         tm.assert_index_equal(df.index.levels[1], expected)
-        assert df.index.names == ["label", "datetime"]
+        assert df.index.names == ("label", "datetime")
 
         df = DataFrame(np.random.default_rng(2).random(6))
         idx1 = DatetimeIndex(

pandas/tests/frame/methods/test_sort_values.py

@@ -874,7 +874,7 @@ def test_sort_index_level_and_column_label(
             )
 
         # Get index levels from df_idx
-        levels = df_idx.index.names
+        levels = list(df_idx.index.names)
 
         # Compute expected by sorting on columns and the setting index
         expected = df_none.sort_values(
@@ -892,7 +892,7 @@ def test_sort_column_level_and_index_label(
         # GH#14353
 
         # Get levels from df_idx
-        levels = df_idx.index.names
+        levels = list(df_idx.index.names)
 
         # Compute expected by sorting on axis=0, setting index levels, and then
         # transposing. For some cases this will result in a frame with

pandas/tests/frame/test_stack_unstack.py

@@ -783,7 +783,7 @@ def test_unstack_multi_level_cols(self):
                 [[10, 20, 30], [10, 20, 40]], names=["i1", "i2", "i3"]
             ),
         )
-        assert df.unstack(["i2", "i1"]).columns.names[-2:] == ["i2", "i1"]
+        assert df.unstack(["i2", "i1"]).columns.names[-2:] == ("i2", "i1")
 
     def test_unstack_multi_level_rows_and_cols(self):
         # PH 28306: Unstack df with multi level cols and rows
@@ -1780,7 +1780,7 @@ def test_stack_unstack_preserve_names(
 
         unstacked = frame.unstack()
         assert unstacked.index.name == "first"
-        assert unstacked.columns.names == ["exp", "second"]
+        assert unstacked.columns.names == ("exp", "second")
 
         restacked = unstacked.stack(future_stack=future_stack)
         assert restacked.index.names == frame.index.names

pandas/tests/generic/test_frame.py

@@ -38,12 +38,12 @@ def test_set_axis_name_mi(self, func):
         level_names = ["L1", "L2"]
 
         result = methodcaller(func, level_names)(df)
-        assert result.index.names == level_names
-        assert result.columns.names == [None, None]
+        assert result.index.names == tuple(level_names)
+        assert result.columns.names == (None, None)
 
         result = methodcaller(func, level_names, axis=1)(df)
-        assert result.columns.names == ["L1", "L2"]
-        assert result.index.names == [None, None]
+        assert result.columns.names == ("L1", "L2")
+        assert result.index.names == (None, None)
 
     def test_nonzero_single_element(self):
         # allow single item via bool method

pandas/tests/generic/test_series.py

@@ -24,9 +24,9 @@ def test_set_axis_name_mi(self, func):
 
         result = methodcaller(func, ["L1", "L2"])(ser)
         assert ser.index.name is None
-        assert ser.index.names == ["l1", "l2"]
+        assert ser.index.names == ("l1", "l2")
         assert result.index.name is None
-        assert result.index.names, ["L1", "L2"]
+        assert result.index.names, ("L1", "L2")
 
     def test_set_axis_name_raises(self):
         ser = Series([1])