diff --git a/tests/testbugs.nim b/tests/testbugs.nim
index c6122e69..dedd0a48 100644
--- a/tests/testbugs.nim
+++ b/tests/testbugs.nim
@@ -20,7 +20,12 @@ type
 proc udp4DataAvailable(transp: DatagramTransport,
                      remote: TransportAddress): Future[void] {.async, gcsafe.} =
   var udata = getUserData[CustomData](transp)
-  if udata.test == "CHECK":
+  var expect = TEST_MSG
+  var data: seq[byte]
+  var datalen: int
+  transp.peekMessage(data, datalen)
+  if udata.test == "CHECK" and datalen == MSG_LEN and
+     equalMem(addr data[0], addr expect[0], datalen):
     udata.test = "OK"
   transp.close()