diff --git a/tests/libtest/first.c b/tests/libtest/first.c
index fe72ab3561..a195a9815a 100644
--- a/tests/libtest/first.c
+++ b/tests/libtest/first.c
@@ -201,7 +201,7 @@ void ws_close(CURL *curl)
 {
   size_t sent;
   CURLcode result = curl_ws_send(curl, "", 0, &sent, 0, CURLWS_CLOSE);
-  curl_mfprintf(stderr, "ws: curl_ws_send returned %u, sent %zu\n",
+  curl_mfprintf(stderr, "ws: curl_ws_send returned %d, sent %zu\n",
                 result, sent);
 }
 #endif /* CURL_DISABLE_WEBSOCKETS */