test_threading.py 文件源码

def test_finalize_with_trace(self):
        # Issue1733757
        # Avoid a deadlock when sys.settrace steps into threading._shutdown
        p = subprocess.Popen([sys.executable, "-c", """if 1:
            import sys, threading

            # A deadlock-killer, to prevent the
            # testsuite to hang forever
            def killer():
                import os, time
                time.sleep(2)
                print 'program blocked; aborting'
                os._exit(2)
            t = threading.Thread(target=killer)
            t.daemon = True
            t.start()

            # This is the trace function
            def func(frame, event, arg):
                threading.current_thread()
                return func

            sys.settrace(func)
            """],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE)
        self.addCleanup(p.stdout.close)
        self.addCleanup(p.stderr.close)
        stdout, stderr = p.communicate()
        rc = p.returncode
        self.assertFalse(rc == 2, "interpreted was blocked")
        self.assertTrue(rc == 0,
                        "Unexpected error: " + repr(stderr))