diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index fcd73f2..01fcb5a 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -634,6 +634,21 @@
     fi
 }
 
+# check if the given command uses gnutls and sets global variable CMD_IS_GNUTLS
+is_gnutls() {
+    case "$1" in
+    *gnutls-cli*)
+        CMD_IS_GNUTLS=1
+        ;;
+    *gnutls-serv*)
+        CMD_IS_GNUTLS=1
+        ;;
+    *)
+        CMD_IS_GNUTLS=0
+        ;;
+    esac
+}
+
 # Compare file content
 # Usage: find_in_both pattern file1 file2
 # extract from file1 the first line matching the pattern
@@ -726,6 +741,30 @@
         esac
     fi
 
+    # update CMD_IS_GNUTLS variable
+    is_gnutls "$SRV_CMD"
+
+    # if the server uses gnutls but doesn't set priority, explicitly
+    # set the default priority
+    if [ "$CMD_IS_GNUTLS" -eq 1 ]; then
+        case "$SRV_CMD" in
+              *--priority*) :;;
+              *) SRV_CMD="$SRV_CMD --priority=NORMAL";;
+        esac
+    fi
+
+    # update CMD_IS_GNUTLS variable
+    is_gnutls "$CLI_CMD"
+
+    # if the client uses gnutls but doesn't set priority, explicitly
+    # set the default priority
+    if [ "$CMD_IS_GNUTLS" -eq 1 ]; then
+        case "$CLI_CMD" in
+              *--priority*) :;;
+              *) CLI_CMD="$CLI_CMD --priority=NORMAL";;
+        esac
+    fi
+
     # fix client port
     if [ -n "$PXY_CMD" ]; then
         CLI_CMD=$( echo "$CLI_CMD" | sed s/+SRV_PORT/$PXY_PORT/g )