Test wouldn't work in debug mode.
We probably need a function in test_support to handle this.
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 6723d00..6e44a28 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -327,6 +327,7 @@
stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
self.assertEqual(stdout, "Woke up, sleep function is: <built-in function sleep>\n")
+ stderr = re.sub(r"^\[\d+ refs\]", "", stderr, re.MULTILINE).strip()
self.assertEqual(stderr, "")