diff --git a/tests/test_security_zap.cpp b/tests/test_security_zap.cpp
index 92987629..49486680 100644
--- a/tests/test_security_zap.cpp
+++ b/tests/test_security_zap.cpp
@@ -64,6 +64,16 @@ static void zap_handler_disconnect (void *ctx)
     zap_handler_generic (ctx, zap_disconnect);
 }
 
+static void zap_handler_do_not_recv (void *ctx)
+{
+    zap_handler_generic (ctx, zap_do_not_recv);
+}
+
+static void zap_handler_do_not_send (void *ctx)
+{
+    zap_handler_generic (ctx, zap_do_not_send);
+}
+
 int expect_new_client_bounce_fail_and_count_monitor_events (
   void *ctx,
   char *my_endpoint,
@@ -344,8 +354,42 @@ void test_zap_errors (socket_config_fn server_socket_config_,
       0, 0,
 #endif
       client_socket_config_, client_socket_config_data_);
-    shutdown_context_and_server_side(ctx, zap_thread, server, server_mon,
-        handler, true);
+    shutdown_context_and_server_side (ctx, zap_thread, server, server_mon,
+                                      handler, true);
+
+    //  ZAP handler does not read request
+    fprintf (stderr,
+             "test_zap_unsuccessful ZAP handler does not read request\n");
+    setup_context_and_server_side (&ctx, &handler, &zap_thread, &server,
+        &server_mon, my_endpoint, &zap_handler_do_not_recv,
+        server_socket_config_);
+    test_zap_unsuccessful_no_handler (
+      ctx, my_endpoint, server, server_mon,
+#ifdef ZMQ_BUILD_DRAFT_API
+      ZMQ_EVENT_HANDSHAKE_FAILED_NO_DETAIL, EPIPE,
+#else
+      0, 0,
+#endif
+      client_socket_config_, client_socket_config_data_);
+    shutdown_context_and_server_side (ctx, zap_thread, server, server_mon,
+                                      handler);
+
+    //  ZAP handler does not send reply
+    fprintf (stderr,
+             "test_zap_unsuccessful ZAP handler does not write reply\n");
+    setup_context_and_server_side (
+      &ctx, &handler, &zap_thread, &server, &server_mon, my_endpoint,
+      &zap_handler_do_not_send, server_socket_config_);
+    test_zap_unsuccessful_no_handler (
+      ctx, my_endpoint, server, server_mon,
+#ifdef ZMQ_BUILD_DRAFT_API
+      ZMQ_EVENT_HANDSHAKE_FAILED_NO_DETAIL, EPIPE,
+#else
+      0, 0,
+#endif
+      client_socket_config_, client_socket_config_data_);
+    shutdown_context_and_server_side (ctx, zap_thread, server, server_mon,
+                                      handler);
 }
 
 int main (void)
diff --git a/tests/testutil_security.hpp b/tests/testutil_security.hpp
index 4586f208..74564ba0 100644
--- a/tests/testutil_security.hpp
+++ b/tests/testutil_security.hpp
@@ -154,7 +154,9 @@ enum zap_protocol_t
     zap_wrong_request_id,
     zap_status_invalid,
     zap_too_many_parts,
-    zap_disconnect
+    zap_disconnect,
+    zap_do_not_recv,
+    zap_do_not_send
 };
 
 void *zap_requests_handled;
@@ -182,8 +184,11 @@ void zap_handler_generic (void *ctx,
       {handler, 0, ZMQ_POLLIN, 0},
     };
 
+    // if ordered not to receive the request, ignore the second poll item
+    const int numitems = (zap_protocol == zap_do_not_recv) ? 1 : 2;
+
     //  Process ZAP requests forever
-    while (zmq_poll (items, 2, -1) >= 0) {
+    while (zmq_poll (items, numitems, -1) >= 0) {
         if (items[0].revents & ZMQ_POLLIN) {
             char *buf = s_recv (control);
             assert (buf);
@@ -198,7 +203,10 @@ void zap_handler_generic (void *ctx,
         if (!version)
             break; //  Terminating - peer's socket closed
         if (zap_protocol == zap_disconnect)
+        {
+            free (version);
             break;
+        }
 
         char *sequence = s_recv (handler);
         char *domain = s_recv (handler);
@@ -268,12 +276,14 @@ void zap_handler_generic (void *ctx,
             if (zap_protocol == zap_too_many_parts) {
                 s_sendmore (handler, "");
             }
-            s_send (handler, "");
+            if (zap_protocol != zap_do_not_send)
+                s_send (handler, "");
         } else {
             s_sendmore (handler, "400");
             s_sendmore (handler, "Invalid client public key");
             s_sendmore (handler, "");
-            s_send (handler, "");
+            if (zap_protocol != zap_do_not_send)
+                s_send(handler, "");
         }
         free (version);
         free (sequence);