diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 09ec8ecad..8f1c5e4ec 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -1341,7 +1341,7 @@ class UnicodeTest(string_tests.CommonTest,
         with self.assertRaises(ValueError):
             result = format(2.34, format_string)
 
-    @unittest.skip("TODO: RUSTPYTHON")
+    @unittest.skip("TODO: RUSTPYTHON, IndexError: tuple index out of range")
     def test_format_huge_item_number(self):
         format_string = "{{{}:.6f}}".format(sys.maxsize + 1)
         with self.assertRaises(ValueError):