Call mbedtls_ssl_set_hostname in the generic endpoint setup in unit tests

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/src/test_helpers/ssl_helpers.c b/tests/src/test_helpers/ssl_helpers.c
index 3cb6175..9a3859d 100644
--- a/tests/src/test_helpers/ssl_helpers.c
+++ b/tests/src/test_helpers/ssl_helpers.c
@@ -855,6 +855,10 @@
     ret = mbedtls_ssl_setup(&(ep->ssl), &(ep->conf));
     TEST_ASSERT(ret == 0);
 
+    if (MBEDTLS_SSL_IS_CLIENT == endpoint_type) {
+        ret = mbedtls_ssl_set_hostname(&(ep->ssl), "localhost");
+    }
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS) && defined(MBEDTLS_SSL_SRV_C)
     if (endpoint_type == MBEDTLS_SSL_IS_SERVER && dtls_context != NULL) {
         mbedtls_ssl_conf_dtls_cookies(&(ep->conf), NULL, NULL, NULL);