Method test_stress_delivery_simultaneous

Lib/test/test_signal.py:1315–1346

This test uses simultaneous signal handlers.

(self)

    @unittest.skipUnless(hasattr(signal, "setitimer"),
                         "test needs setitimer()")
    def test_stress_delivery_simultaneous(self):
        """
        This test uses simultaneous signal handlers.
        """
        N = self.decide_itimer_count()
        sigs = []

        def handler(signum, frame):
            sigs.append(signum)

        # On Android, SIGUSR1 is unreliable when used in close proximity to
        # another signal – see Android/testbed/app/src/main/python/main.py.
        # So we use a different signal.
        self.setsig(signal.SIGUSR2, handler)
        self.setsig(signal.SIGALRM, handler)  # for ITIMER_REAL

        expected_sigs = 0
        while expected_sigs < N:
            # Hopefully the SIGALRM will be received somewhere during
            # initial processing of SIGUSR2.
            signal.setitimer(signal.ITIMER_REAL, 1e-6 + random.random() * 1e-5)
            os.kill(os.getpid(), signal.SIGUSR2)

            expected_sigs += 2
            # Wait for handlers to run to avoid signal coalescing
            for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
                if len(sigs) >= expected_sigs:
                    break

        # All ITIMER_REAL signals should have been delivered to the
        # Python handler
        self.assertEqual(len(sigs), N, "Some signals were lost")

    @support.requires_gil_enabled("gh-121065: test is flaky on free-threaded build")
    @unittest.skipIf(is_apple, "crashes due to system bug (FB13453490)")