test_break.py 文件源码

def testHandlerReplacedButCalled(self):
        # Can't use skipIf decorator because the signal handler may have
        # been changed after defining this method.
        if signal.getsignal(signal.SIGINT) == signal.SIG_IGN:
            self.skipTest("test requires SIGINT to not be ignored")
        # If our handler has been replaced (is no longer installed) but is
        # called by the *new* handler, then it isn't safe to delay the
        # SIGINT and we should immediately delegate to the default handler
        unittest.installHandler()

        handler = signal.getsignal(signal.SIGINT)
        def new_handler(frame, signum):
            handler(frame, signum)
        signal.signal(signal.SIGINT, new_handler)

        try:
            pid = os.getpid()
            os.kill(pid, signal.SIGINT)
        except KeyboardInterrupt:
            pass
        else:
            self.fail("replaced but delegated handler doesn't raise interrupt")