ssl-opt.sh: Add a check of the list of supported ciphersuites

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 55e465a..81c6c60 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -279,9 +279,18 @@
 
 # Space-separated list of ciphersuites supported by this build of
 # Mbed TLS.
-P_CIPHERSUITES=" $($P_CLI help_ciphersuites 2>/dev/null |
-                   grep TLS- |
-                   tr -s ' \n' ' ')"
+P_CIPHERSUITES=""
+if [ "$LIST_TESTS" -eq 0 ]; then
+    P_CIPHERSUITES=" $($P_CLI help_ciphersuites 2>/dev/null |
+                       grep 'TLS-' |
+                       tr -s ' \n' ' ')"
+
+    if [ -z "${P_CIPHERSUITES# }" ]; then
+        echo >&2 "$0: fatal error: no cipher suites found!"
+        exit 125
+    fi
+fi
+
 requires_ciphersuite_enabled() {
     case $P_CIPHERSUITES in
         *" $1 "*) :;;