There is a race condition in FAIL: test_signal_handling_args (test.test_asyncio.test_events.KqueueEventLoopTests) in macOS:

https://buildbot.python.org/all/#/builders/147/builds/546/steps/4/logs/stdio

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FAIL: test_signal_handling_args (test.test_asyncio.test_events.KqueueEventLoopTests)
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Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.7.billenstein-sierra/build/Lib/test/test_asyncio/test_events.py", line 595, in test_signal_handling_args
    self.assertEqual(caught, 1)
AssertionError: 0 != 1

It seems that SIGALRM is never received in the 0.5 seconds of timeout:

    def test_signal_handling_args(self):
        some_args = (42,)
        caught = 0

        def my_handler(*args):
            nonlocal caught
            caught += 1
            self.assertEqual(args, some_args)

        self.loop.add_signal_handler(signal.SIGALRM, my_handler, *some_args)

        signal.setitimer(signal.ITIMER_REAL, 0.1, 0)  # Send SIGALRM once.
        self.loop.call_later(0.5, self.loop.stop)
        self.loop.run_forever()
        self.assertEqual(caught, 1)

Maybe we should set up a much bigger timeout and make the handle stop the event loop.