gh-130737: Fix multiprocessing test_notify() (#130797)

Replace hardcoded delay (100 ms) with a loop awaiting until a
condition is true: replace assertReturnsIfImplemented() with
assertReachesEventually().

Use sleeping_retry() in assertReachesEventually() to tolerate slow
buildbots and raise an exception on timeout (30 seconds).

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index cafbc757904f641947cac371871ac13250abc3ef..f31151e53c4bb06ee960b96b7ddae5a67673d43a 100644 (file)
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -1622,14 +1622,13 @@ class _TestCondition(BaseTestCase):
         cond.release()
 
     def assertReachesEventually(self, func, value):
-        for i in range(10):
+        for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
             try:
                 if func() == value:
                     break
             except NotImplementedError:
                 break
-            time.sleep(DELTA)
-        time.sleep(DELTA)
+
         self.assertReturnsIfImplemented(value, func)
 
     def check_invariant(self, cond):
@@ -1663,8 +1662,7 @@ class _TestCondition(BaseTestCase):
         sleeping.acquire()
 
         # check no process/thread has woken up
-        time.sleep(DELTA)
-        self.assertReturnsIfImplemented(0, get_value, woken)
+        self.assertReachesEventually(lambda: get_value(woken), 0)
 
         # wake up one process/thread
         cond.acquire()
@@ -1672,8 +1670,7 @@ class _TestCondition(BaseTestCase):
         cond.release()
 
         # check one process/thread has woken up
-        time.sleep(DELTA)
-        self.assertReturnsIfImplemented(1, get_value, woken)
+        self.assertReachesEventually(lambda: get_value(woken), 1)
 
         # wake up another
         cond.acquire()
@@ -1681,8 +1678,7 @@ class _TestCondition(BaseTestCase):
         cond.release()
 
         # check other has woken up
-        time.sleep(DELTA)
-        self.assertReturnsIfImplemented(2, get_value, woken)
+        self.assertReachesEventually(lambda: get_value(woken), 2)
 
         # check state is not mucked up
         self.check_invariant(cond)