def test_reply_error_empty_message():
s = str(nbd.ReplyError(5, ""))
assert s == "Server error: [Error 5] Input/output error"
def test_reply_error_simple():
s = str(nbd.ReplyError(1, "Simple reply failed"))
assert s == "Simple reply failed: [Error 1] Operation not permitted"
def test_reply_error_unknown_code():
s = str(nbd.ReplyError(-1, "bad error"))
assert s == "Bad error: [Error -1] Unknown error -1"
def test_reply_error_structured():
s = str(nbd.ReplyError(28, "writing to file failed"))
assert s == "Writing to file failed: [Error 28] No space left on device"
