test_socket.py 文件源码

def testCMSG_SPACE(self):
        # Test CMSG_SPACE() with various valid and invalid values,
        # checking the assumptions used by sendmsg().
        toobig = self.socklen_t_limit - socket.CMSG_SPACE(1) + 1
        values = list(range(257)) + list(range(toobig - 257, toobig))

        last = socket.CMSG_SPACE(0)
        # struct cmsghdr has at least three members, two of which are ints
        self.assertGreater(last, array.array("i").itemsize * 2)
        for n in values:
            ret = socket.CMSG_SPACE(n)
            self.assertGreaterEqual(ret, last)
            self.assertGreaterEqual(ret, socket.CMSG_LEN(n))
            self.assertGreaterEqual(ret, n + socket.CMSG_LEN(0))
            self.assertLessEqual(ret, self.socklen_t_limit)
            last = ret

        self.assertRaises(OverflowError, socket.CMSG_SPACE, -1)
        # sendmsg() shares code with these functions, and requires
        # that it reject values over the limit.
        self.assertRaises(OverflowError, socket.CMSG_SPACE, toobig)
        self.assertRaises(OverflowError, socket.CMSG_SPACE, sys.maxsize)