Linked list sorting (?)

leetcode/test_stuff.py

@@ -1,6 +1,7 @@
 import pytest
 
 import stuff
+import stdlib
 
 
 @pytest.mark.parametrize(
@@ -77,3 +78,27 @@ def test_min_stack(ops: list[tuple[str] | tuple[str, int]], expected: list[int |
         returned.append(getattr(inst, method)(arg))
 
     assert returned == expected
+
+
+@pytest.mark.parametrize(
+    ("head", "expected"),
+    [
+        (None, None),
+        (
+            stdlib.ListNode(
+                4, stdlib.ListNode(2, stdlib.ListNode(1, stdlib.ListNode(3)))
+            ),
+            stdlib.ListNode(
+                1, stdlib.ListNode(2, stdlib.ListNode(3, stdlib.ListNode(4)))
+            ),
+        ),
+    ],
+)
+def test_sort_linked_list(head: stdlib.ListNode | None, expected: stdlib.ListNode | None):
+    if head is None:
+        assert stuff.sort_linked_list(head) == expected
+        return
+
+    assert stuff.linked_list_to_list(
+        stuff.sort_linked_list(head)
+    ) == stuff.linked_list_to_list(expected)