def test_multi_process(self):
        # This test can't work on twisted because we use the global reactor
        # and have no way to get it back into a sane state after the fork.
        skip_if_twisted()
        with ExpectLog(gen_log, "(Starting .* processes|child .* exited|uncaught exception)"):
            self.assertFalse(IOLoop.initialized())
            sock, port = bind_unused_port()

            def get_url(path):
                return "http://127.0.0.1:%d%s" % (port, path)
            # ensure that none of these processes live too long
            signal.alarm(5)  # master process
            try:
                id = fork_processes(3, max_restarts=3)
                self.assertTrue(id is not None)
                signal.alarm(5)  # child processes
            except SystemExit as e:
                # if we exit cleanly from fork_processes, all the child processes
                # finished with status 0
                self.assertEqual(e.code, 0)
                self.assertTrue(task_id() is None)
                sock.close()
                return
            try:
                if id in (0, 1):
                    self.assertEqual(id, task_id())
                    server = HTTPServer(self.get_app())
                    server.add_sockets([sock])
                    IOLoop.instance().start()
                elif id == 2:
                    self.assertEqual(id, task_id())
                    sock.close()
                    # Always use SimpleAsyncHTTPClient here; the curl
                    # version appears to get confused sometimes if the
                    # connection gets closed before it's had a chance to
                    # switch from writing mode to reading mode.
                    client = HTTPClient(SimpleAsyncHTTPClient)

                    def fetch(url, fail_ok=False):
                        try:
                            return client.fetch(get_url(url))
                        except HTTPError as e:
                            if not (fail_ok and e.code == 599):
                                raise

                    # Make two processes exit abnormally
                    fetch("/?exit=2", fail_ok=True)
                    fetch("/?exit=3", fail_ok=True)

                    # They've been restarted, so a new fetch will work
                    int(fetch("/").body)

                    # Now the same with signals
                    # Disabled because on the mac a process dying with a signal
                    # can trigger an "Application exited abnormally; send error
                    # report to Apple?" prompt.
                    # fetch("/?signal=%d" % signal.SIGTERM, fail_ok=True)
                    # fetch("/?signal=%d" % signal.SIGABRT, fail_ok=True)
                    # int(fetch("/").body)

                    # Now kill them normally so they won't be restarted
                    fetch("/?exit=0", fail_ok=True)
                    # One process left; watch it's pid change
                    pid = int(fetch("/").body)
                    fetch("/?exit=4", fail_ok=True)
                    pid2 = int(fetch("/").body)
                    self.assertNotEqual(pid, pid2)

                    # Kill the last one so we shut down cleanly
                    fetch("/?exit=0", fail_ok=True)

                    os._exit(0)
            except Exception:
                logging.error("exception in child process %d", id, exc_info=True)
                raise
dataset/ETHPy150Open cloudaice/simple-data/misc/virtenv/lib/python2.7/site-packages/tornado/test/process_test.py/ProcessTest.test_multi_process/original