diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 412f42c..51974f6 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -354,7 +354,7 @@
     case "$2" in
         *openssl*s_server*) s='-psk abc123 -nocert';;
         *openssl*) s='-psk abc123';;
-        *gnutls-*) s='--pskkey=abc123';;
+        *gnutls-*) s='--pskusername=Client_identity --pskkey=abc123';;
         *) s='psk=abc123';;
     esac
     eval $1='"$2 $s"'