fix(test): Deterministic explode output by sorting on multiple columns (#2988)

Author: FBruzzesi

tests/frame/explode_test.py

@@ -46,39 +46,39 @@ def test_explode_single_col(
         .with_columns(nw.col(column).cast(nw.List(nw.Int32())))
         .explode(column)
         .select("a", column)
-        .sort("a")
+        .sort("a", column, nulls_last=True)
     )
     expected = {"a": ["w", "x", "x", "y", "z"], column: expected_values}
     assert_equal_data(result, expected)
 
 
 @pytest.mark.parametrize(
-    ("columns", "more_columns", "expected"),
+    ("column", "more_columns", "expected"),
     [
         (
             "l1",
             ["l2"],
             {
-                "a": ["x", "x", "y", "z", "w"],
-                "l1": [1, 2, None, None, None],
-                "l2": [3, None, None, 42, None],
+                "a": ["w", "x", "x", "y", "z"],
+                "l1": [None, 1, 2, None, None],
+                "l2": [None, 3, None, None, 42],
             },
         ),
         (
             "l3",
             ["l4"],
             {
-                "a": ["x", "x", "y", "z", "w"],
-                "l3": [1, 2, 3, None, 1],
-                "l4": [1, 2, 3, 123, 456],
+                "a": ["w", "x", "x", "y", "z"],
+                "l3": [1, 1, 2, 3, None],
+                "l4": [456, 1, 2, 3, 123],
             },
         ),
     ],
 )
 def test_explode_multiple_cols(
     request: pytest.FixtureRequest,
     constructor: Constructor,
-    columns: str | Sequence[str],
+    column: str,
     more_columns: Sequence[str],
     expected: dict[str, list[str | int | None]],
 ) -> None:
@@ -93,9 +93,10 @@ def test_explode_multiple_cols(
 
     result = (
         nw.from_native(constructor(data))
-        .with_columns(nw.col(columns, *more_columns).cast(nw.List(nw.Int32())))
-        .explode(columns, *more_columns)
-        .select("a", columns, *more_columns)
+        .with_columns(nw.col(column, *more_columns).cast(nw.List(nw.Int32())))
+        .explode(column, *more_columns)
+        .select("a", column, *more_columns)
+        .sort("a", column, nulls_last=True)
     )
     assert_equal_data(result, expected)