Add test for small server packet

To allow testing with ECDHE-ECDSA with DTLS
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 4d39041..6faf61a 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -5945,6 +5945,13 @@
             0 \
             -c "Read from server: 1 bytes read"
 
+run_test    "Small server packet DTLS, ECDHE-ECDSA" \
+            "$P_SRV dtls=1 response_size=1" \
+            "$P_CLI dtls=1 \
+             force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
+            0 \
+            -c "Read from server: 1 bytes read"
+
 # A test for extensions in SSLv3
 
 requires_config_enabled MBEDTLS_SSL_PROTO_SSL3