pypy.module.posix.test.apptest_posix:test_fork_warns_when_threads_active

def test_fork_warns_when_threads_active():
        # avoid importing 'threading'/'warnings' (expensive untranslated):
        # use _thread directly, and register a minimal stand-in module
        # under sys.modules['warnings'] with just enough of the real
        # warnings module's interface (_showwarnmsg + WarningMessage) for
        # _warnings.warn() to report through instead of writing to stderr.
        import _thread
        import _warnings
        import _signal
        import sys
        import time
    
        # fork()+threads is inherently hang-prone (that's the whole point
        # of the warning under test); bound the worst case so a stuck run
        # fails loudly instead of hanging the rest of the test suite.
        def on_alarm(sig, frame):
            raise RuntimeError("test_fork_warns_when_threads_active timed out")
        old_alarm_handler = _signal.signal(_signal.SIGALRM, on_alarm)
        _signal.alarm(10)
        try:
            ready = _thread.allocate_lock()
            ready.acquire()
            stop = []
            def background_thread():
                ready.release()
                # bounded (~5s) so it self-terminates even if something odd
                # happens to thread scheduling around the fork() below
                for _ in range(500):
                    if stop:
                        break
                    time.sleep(0.01)
    
            _thread.start_new(background_thread, ())
            ready.acquire()  # wait until the thread actually started
    
            class FakeWarningMessage:
                def __init__(self, message, category, filename, lineno,
                             file=None, line=None, source=None):
                    self.message = message
                    self.category = category
    
            captured = []
            class FakeWarningsModule:
                WarningMessage = FakeWarningMessage
                def _showwarnmsg(self, msg):
                    captured.append(msg)
    
            old_filters = _warnings.filters[:]
            old_warnings_mod = sys.modules.get('warnings')
            sys.modules['warnings'] = FakeWarningsModule()
            _warnings.filters.insert(0, ('always', None, DeprecationWarning, None, 0))
            _warnings._filters_mutated()
            try:
                pid = os.fork()
                if pid == 0:
                    os._exit(0)
            finally:
                if old_warnings_mod is not None:
                    sys.modules['warnings'] = old_warnings_mod
                else:
                    del sys.modules['warnings']
                _warnings.filters[:] = old_filters
                _warnings._filters_mutated()
                stop.append(1)
    
>           assert len(captured) == 1
E           assert 0 == 1
E            +  where 0 = len([])

../build/pypy/module/posix/test/apptest_posix.py:113: AssertionError

builder: pypy-c-jit-macos-arm64 build #1393+

test: pypy.module.posix.test.apptest_posix:test_fork_warns_when_threads_active