Fix test

Author: youknowone

Lib/test/test_winreg.py

@@ -3,6 +3,7 @@
 
 import gc
 import os, sys, errno
+import itertools
 import threading
 import unittest
 from platform import machine, win32_edition
@@ -322,42 +323,33 @@ def test_queryvalueex_race_condition(self):
         # gh-142282: QueryValueEx could read garbage buffer under race
         # condition when another thread changes the value size
         done = False
-        error_found = None
+        ready = threading.Event()
         values = [b'ham', b'spam']
 
         class WriterThread(threading.Thread):
             def run(self):
                 with CreateKey(HKEY_CURRENT_USER, test_key_name) as key:
-                    use_first = True
+                    values_iter = itertools.cycle(values)
                     while not done:
-                        val = values[0] if use_first else values[1]
-                        use_first = not use_first
+                        val = next(values_iter)
                         SetValueEx(key, 'test_value', 0, REG_BINARY, val)
+                        ready.set()
 
         thread = WriterThread()
         thread.start()
         try:
+            ready.wait()
             with CreateKey(HKEY_CURRENT_USER, test_key_name) as key:
                 for _ in range(1000):
-                    try:
-                        result, typ = QueryValueEx(key, 'test_value')
-                    except FileNotFoundError:
-                        # Value not yet created
-                        continue
+                    result, typ = QueryValueEx(key, 'test_value')
                     # The result must be one of the written values,
                     # not garbage data from uninitialized buffer
-                    if result not in values:
-                        error_found = result
-                        break
+                    self.assertIn(result, values, f"QueryValueEx returned unexpected value: {result!r}")
         finally:
             done = True
             thread.join()
             DeleteKey(HKEY_CURRENT_USER, test_key_name)
 
-        if error_found is not None:
-            self.fail(f"QueryValueEx returned unexpected value: {error_found!r}, "
-                      f"expected one of {values}")
-
     def test_long_key(self):
         # Issue2810, in 2.6 and 3.1 when the key name was exactly 256
         # characters, EnumKey raised "WindowsError: More data is