Issue #11185: Fix test_wait4 under AIX. Patch by Sébastien Sablé.

Lib/test/test_wait4.py

@@ -3,6 +3,7 @@
 
 import os
 import time
+import sys
 from test.fork_wait import ForkWait
 from test.support import run_unittest, reap_children, get_attribute
 
@@ -13,10 +14,15 @@ get_attribute(os, 'wait4')
 
 class Wait4Test(ForkWait):
     def wait_impl(self, cpid):
+        option = os.WNOHANG
+        if sys.platform.startswith('aix'):
+            # Issue #11185: wait4 is broken on AIX and will always return 0
+            # with WNOHANG.
+            option = 0
         for i in range(10):
             # wait4() shouldn't hang, but some of the buildbots seem to hang
             # in the forking tests.  This is an attempt to fix the problem.
-            spid, status, rusage = os.wait4(cpid, os.WNOHANG)
+            spid, status, rusage = os.wait4(cpid, option)
             if spid == cpid:
                 break
             time.sleep(1.0)

Misc/NEWS

@@ -155,6 +155,8 @@ IDLE
 Tests
 -----
 
+- Issue #11185: Fix test_wait4 under AIX.  Patch by Sébastien Sablé.
+
 - Issue #17691: test_univnewlines now works with unittest test discovery.
   Patch by Zachary Ware.