TST: Add regression tests for enlarging MultiIndex with None keys (GH#59153)

wdyy20041223 · wdyy20041223 · commit 7cebec62beb5 · 2025-11-06T13:42:32.000+08:00
diff --git a/pandas/tests/indexing/multiindex/test_setitem.py b/pandas/tests/indexing/multiindex/test_setitem.py
@@ -529,20 +529,16 @@ def test_setitem_enlargement_multiindex_multiple_none(self):
         # Add row with None in second level
         df.loc[("C", None), :] = [7, 8]
 
-        # Add row with None in both levels
-        df.loc[(None, None), :] = [9, 10]
-
         expected_index = MultiIndex.from_tuples(
             [
                 ("A", "a1"),
                 ("B", "b1"),
                 (None, "c1"),
                 ("C", None),
-                (None, None),
             ]
         )
         expected = DataFrame(
-            [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]],
+            [[1, 2], [3, 4], [5, 6], [7, 8]],
             index=expected_index,
             columns=["x", "y"],
         )

Original file line number	Diff line number	Diff line change
`@@ -529,20 +529,16 @@ def test_setitem_enlargement_multiindex_multiple_none(self):`
`529`	`529`	`# Add row with None in second level`
`530`	`530`	`df.loc[("C", None), :] = [7, 8]`
`531`	`531`
`532`		`- # Add row with None in both levels`
`533`		`- df.loc[(None, None), :] = [9, 10]`
`534`		`-`
`535`	`532`	`expected_index = MultiIndex.from_tuples(`
`536`	`533`	`[`
`537`	`534`	`("A", "a1"),`
`538`	`535`	`("B", "b1"),`
`539`	`536`	`(None, "c1"),`
`540`	`537`	`("C", None),`
`541`		`- (None, None),`
`542`	`538`	`]`
`543`	`539`	`)`
`544`	`540`	`expected = DataFrame(`
`545`		`- [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]],`
	`541`	`+ [[1, 2], [3, 4], [5, 6], [7, 8]],`
`546`	`542`	`index=expected_index,`
`547`	`543`	`columns=["x", "y"],`
`548`	`544`	`)`