Problem: test does not trigger HWM

Solution: modify order of operations, add diagnostic output

tests/test_router_mandatory.cpp

@@ -32,34 +32,44 @@
 void test_get_peer_state ()
 {
 #ifdef ZMQ_BUILD_DRAFT_API
-    size_t len = MAX_SOCKET_STRING;
-    char my_endpoint[MAX_SOCKET_STRING];
     void *ctx = zmq_ctx_new ();
     assert (ctx);
     void *router = zmq_socket (ctx, ZMQ_ROUTER);
     assert (router);
 
-    int rc = zmq_bind (router, "tcp://127.0.0.1:*");
-    assert (rc == 0);
-
-    rc = zmq_getsockopt (router, ZMQ_LAST_ENDPOINT, my_endpoint, &len);
-    assert (rc == 0);
-
+    int rc;
     int mandatory = 1;
     rc = zmq_setsockopt (router, ZMQ_ROUTER_MANDATORY, &mandatory,
                          sizeof (mandatory));
 
-    //  Create dealer called "X" and connect it to our router
+    rc = zmq_bind (router, "tcp://127.0.0.1:*");
+    assert (rc == 0);
+
+    size_t my_endpoint_len = MAX_SOCKET_STRING;
+    char my_endpoint[MAX_SOCKET_STRING];
+    rc =
+      zmq_getsockopt (router, ZMQ_LAST_ENDPOINT, my_endpoint, &my_endpoint_len);
+    assert (rc == 0);
+
     void *dealer1 = zmq_socket (ctx, ZMQ_DEALER);
     assert (dealer1);
+
+    void *dealer2 = zmq_socket (ctx, ZMQ_DEALER);
+    assert (dealer2);
+
+    //  Lower HWMs to allow doing the test with fewer messages
+    int hwm = 100;
+    zmq_setsockopt (router, ZMQ_SNDHWM, &hwm, sizeof (int));
+    zmq_setsockopt (dealer1, ZMQ_RCVHWM, &hwm, sizeof (int));
+    zmq_setsockopt (dealer2, ZMQ_RCVHWM, &hwm, sizeof (int));
+
+    //  Name dealer1 "X" and connect it to our router
     rc = zmq_setsockopt (dealer1, ZMQ_IDENTITY, "X", 1);
     assert (rc == 0);
     rc = zmq_connect (dealer1, my_endpoint);
     assert (rc == 0);
 
-    //  Create dealer called "Y" and connect it to our router
-    void *dealer2 = zmq_socket (ctx, ZMQ_DEALER);
-    assert (dealer2);
+    //  Name dealer2 "Y" and connect it to our router
     rc = zmq_setsockopt (dealer2, ZMQ_IDENTITY, "Y", 1);
     assert (rc == 0);
     rc = zmq_connect (dealer2, my_endpoint);
@@ -83,7 +93,6 @@ void test_get_peer_state ()
     rc = zmq_recv (router, buffer, 255, 0);
     assert (rc == 5);
 
-
     void *poller = zmq_poller_new ();
     assert (poller);
 
@@ -95,41 +104,53 @@ void test_get_peer_state ()
 
     const size_t count = 10000;
     const size_t event_size = 2;
+    bool dealer2_blocked = false;
+    size_t dealer1_sent = 0, dealer2_sent = 0, dealer1_received = 0;
     zmq_poller_event_t events[event_size];
-    for (size_t iterations = 0;
-         iterations < count
-         && zmq_poller_wait_all (poller, events, event_size, -1) != -1;
-         ++iterations) {
+    for (size_t iterations = 0; iterations < count; ++iterations) {
+        rc = zmq_poller_wait_all (poller, events, event_size, -1);
+        assert (rc != -1);
         for (size_t i = 0; i < event_size; ++i) {
-            if (events[i].socket == router) {
+            if (events[i].socket == router && events[i].events & ZMQ_POLLOUT) {
                 rc = zmq_socket_get_peer_state (router, "X", 1);
                 if (rc == -1)
                     printf ("zmq_socket_get_peer_state failed: %i\n", errno);
                 assert (rc != -1);
                 if (rc & ZMQ_POLLOUT) {
-                    rc = zmq_send (router, "X", 1, ZMQ_SNDMORE);
+                    rc = zmq_send (router, "X", 1, ZMQ_SNDMORE | ZMQ_DONTWAIT);
                     assert (rc == 1);
-                    rc = zmq_send (router, "Hello", 5, 0);
+                    rc = zmq_send (router, "Hello", 5, ZMQ_DONTWAIT);
                     assert (rc == 5);
+
+                    ++dealer1_sent;
                 }
+
                 rc = zmq_socket_get_peer_state (router, "Y", 1);
                 if (rc == -1)
                     printf ("zmq_socket_get_peer_state failed: %i\n", errno);
                 assert (rc != -1);
                 if (rc & ZMQ_POLLOUT) {
-                    rc = zmq_send (router, "Y", 1, ZMQ_SNDMORE);
+                    rc = zmq_send (router, "Y", 1, ZMQ_SNDMORE | ZMQ_DONTWAIT);
                     assert (rc == 1);
-                    rc = zmq_send (router, "Hello", 5, 0);
+                    rc = zmq_send (router, "Hello", 5, ZMQ_DONTWAIT);
                     assert (rc == 5);
+                    ++dealer2_sent;
+                } else {
+                    dealer2_blocked = true;
                 }
             }
-            if (events[i].socket == dealer1) {
+            if (events[i].socket == dealer1 && events[i].events & ZMQ_POLLIN) {
                 rc = zmq_recv (dealer1, buffer, 255, ZMQ_DONTWAIT);
                 assert (rc == 5);
+
+                ++dealer1_received;
             }
             // never read from dealer2, so its pipe becomes full eventually
         }
     }
+    printf ("dealer1_sent = %zu, dealer2_sent = %zu, dealer1_received = %zu\n",
+            dealer1_sent, dealer2_sent, dealer1_received);
+    assert (dealer2_blocked);
     zmq_poller_destroy (&poller);
 
     rc = zmq_close (router);
@@ -217,5 +238,5 @@ int main (void)
     test_basic ();
     test_get_peer_state ();
 
-    return 0 ;
+    return 0;
 }