test_io.py 文件源码

def check_interrupted_read_retry(self, decode, **fdopen_kwargs):
        """Check that a buffered read, when it gets interrupted (either
        returning a partial result or EINTR), properly invokes the signal
        handler and retries if the latter returned successfully."""
        r, w = os.pipe()
        fdopen_kwargs["closefd"] = False
        def alarm_handler(sig, frame):
            os.write(w, b"bar")
        signal.signal(signal.SIGALRM, alarm_handler)
        try:
            rio = self.io.open(r, **fdopen_kwargs)
            os.write(w, b"foo")
            signal.alarm(1)
            # Expected behaviour:
            # - first raw read() returns partial b"foo"
            # - second raw read() returns EINTR
            # - third raw read() returns b"bar"
            self.assertEqual(decode(rio.read(6)), "foobar")
        finally:
            rio.close()
            os.close(w)
            os.close(r)