Serialise test_connect_delay

Simplify the test connect delay test script, removing the threads and
moving to a serialised version. AFAICS this should provide the same
test, but without the race conditions that happened with the previous
test.

tests/test_connect_delay.cpp

@@ -25,114 +25,10 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 #include <string.h>
 #include <unistd.h>
 #include <string>
-#include <pthread.h>
 
 #undef NDEBUG
 #include <assert.h>
 
-static void *server (void *)
-{
-    void *socket, *context;
-    char buffer[16];
-    int rc, val;
-
-    context = zmq_init (1);
-    assert (context);
-
-    socket = zmq_socket (context, ZMQ_PULL);
-    assert (socket);
-
-    val = 0;
-    rc = zmq_setsockopt(socket, ZMQ_LINGER, &val, sizeof(val));
-    assert (rc == 0);
-
-    rc = zmq_bind (socket, "ipc:///tmp/recon");
-    assert (rc == 0);
-
-    memset (&buffer, 0, sizeof(buffer));
-    rc = zmq_recv (socket, &buffer, sizeof(buffer), 0);
-
-    // Intentionally bail out
-    rc = zmq_close (socket);
-    assert (rc == 0);
-
-    rc = zmq_term (context);
-    assert (rc == 0);
-
-    usleep (200000);
-
-    context = zmq_init (1);
-    assert (context);
-
-    socket = zmq_socket (context, ZMQ_PULL);
-    assert (socket);
-
-    val = 0;
-    rc = zmq_setsockopt(socket, ZMQ_LINGER, &val, sizeof(val));
-    assert (rc == 0);
-
-    rc = zmq_bind (socket, "ipc:///tmp/recon");
-    assert (rc == 0);
-
-    usleep (200000);
-
-    memset (&buffer, 0, sizeof(buffer));
-    rc = zmq_recv (socket, &buffer, sizeof(buffer), ZMQ_DONTWAIT);
-    assert (rc != -1);
-
-    // Start closing the socket while the connecting process is underway.
-    rc = zmq_close (socket);
-    assert (rc == 0);
-
-    rc = zmq_term (context);
-    assert (rc == 0);
-
-    return NULL;
-}
-
-static void *worker (void *)
-{
-    void *socket, *context;
-    int rc, hadone, val;
-
-    context = zmq_init (1);
-    assert (context);
-
-    socket = zmq_socket (context, ZMQ_PUSH);
-    assert (socket);
-
-    val = 0;
-    rc = zmq_setsockopt(socket, ZMQ_LINGER, &val, sizeof(val));
-    assert (rc == 0);
-
-    val = 1;
-    rc = zmq_setsockopt (socket, ZMQ_DELAY_ATTACH_ON_CONNECT, &val, sizeof(val));
-    assert (rc == 0);
-
-    rc = zmq_connect (socket, "ipc:///tmp/recon");
-    assert (rc == 0);
-
-    hadone = 0;
-    // Not checking RC as some may be -1
-    for (int i = 0; i < 6; i++) {
-        usleep(200000);
-        rc = zmq_send (socket, "hi", 2, ZMQ_DONTWAIT);
-        if (rc != -1)
-            hadone ++;
-    }
-
-    assert (hadone >= 2);
-    assert (hadone < 4);
-
-    rc = zmq_close (socket);
-    assert (rc == 0);
-
-    rc = zmq_term (context);
-    assert (rc == 0);
-
-    return NULL;
-}
-
 int main (void)
 {
     fprintf (stderr, "test_connect_delay running...\n");
@@ -141,11 +37,19 @@ int main (void)
     char buffer[16];
     int seen = 0;
 
+    // TEST 1. 
+    // First we're going to attempt to send messages to two
+    // pipes, one connected, the other not. We should see
+    // the PUSH load balancing to both pipes, and hence half
+    // of the messages getting queued, as connect() creates a
+    // pipe immediately. 
+    
     void *context = zmq_ctx_new();
     assert (context);
     void *to = zmq_socket(context, ZMQ_PULL);
     assert (to);
 
+    // Bind the one valid receiver
     val = 0;
     rc = zmq_setsockopt(to, ZMQ_LINGER, &val, sizeof(val));
     assert (rc == 0);
@@ -158,11 +62,15 @@ int main (void)
 
     val = 0;
     zmq_setsockopt (from, ZMQ_LINGER, &val, sizeof(val));
+    // This pipe will not connect
     rc = zmq_connect (from, "tcp://localhost:5556");
     assert (rc == 0);
+    // This pipe will 
     rc = zmq_connect (from, "tcp://localhost:5555");
     assert (rc == 0);
 
+    // We send 10 messages, 5 should just get stuck in the queue
+    // for the not-yet-connected pipe
     for (int i = 0; i < 10; ++i)
     {
         std::string message("message ");
@@ -171,7 +79,11 @@ int main (void)
         assert(rc >= 0);
     }
 
+    // Sleep to allow the messages to be delivered
     zmq_sleep (1);
+    
+    // We now consume from the connected pipe
+    // - we should see just 5
     seen = 0;
     for (int i = 0; i < 10; ++i)
     {
@@ -192,9 +104,17 @@ int main (void)
     rc = zmq_ctx_destroy(context);
     assert (rc == 0);
 
+    // TEST 2
+    // This time we will do the same thing, connect two pipes, 
+    // one of which will succeed in connecting to a bound 
+    // receiver, the other of which will fail. However, we will 
+    // also set the delay attach on connect flag, which should 
+    // cause the pipe attachment to be delayed until the connection
+    // succeeds. 
     context = zmq_ctx_new();
     fprintf (stderr, " Rerunning with DELAY_ATTACH_ON_CONNECT\n");
 
+    // Bind the valid socket
     to = zmq_socket (context, ZMQ_PULL);
     assert (to);
     rc = zmq_bind (to, "tcp://*:5560");
@@ -212,16 +132,19 @@ int main (void)
     rc = zmq_setsockopt (from, ZMQ_LINGER, &val, sizeof(val));
     assert (rc == 0);
 
+    // Set the key flag
     val = 1;
     rc = zmq_setsockopt (from, ZMQ_DELAY_ATTACH_ON_CONNECT, &val, sizeof(val));
     assert (rc == 0);
 
+    // Connect to the invalid socket
     rc = zmq_connect (from, "tcp://localhost:5561");
     assert (rc == 0);
-
+    // Connect to the valid socket
     rc = zmq_connect (from, "tcp://localhost:5560");
     assert (rc == 0);
 
+    // Send 10 messages, all should be routed to the connected pipe
     for (int i = 0; i < 10; ++i)
     {
         std::string message("message ");
@@ -230,13 +153,16 @@ int main (void)
         assert (rc >= 0);
     }
 
+    // Sleep to allow the messages to be delivered
     zmq_sleep (1);
 
+    // Send 10 messages, all should arrive. 
     seen = 0;
     for (int i = 0; i < 10; ++i)
     {
         memset(&buffer, 0, sizeof(buffer));
         rc = zmq_recv (to, &buffer, sizeof(buffer), ZMQ_DONTWAIT);
+        // If there is a failed delivery, assert!
         assert (rc != -1);
     }
 
@@ -249,15 +175,86 @@ int main (void)
     rc = zmq_ctx_destroy(context);
     assert (rc == 0);
 
+    // TEST 3
+    // This time we want to validate that the same blocking behaviour
+    // occurs with an existing connection that is broken. We will send
+    // messaages to a connected pipe, disconnect and verify the messages
+    // block. Then we reconnect and verify messages flow again.
+    context = zmq_ctx_new();
+    void *context2 = zmq_ctx_new();
     fprintf (stderr, " Running DELAY_ATTACH_ON_CONNECT with disconnect\n");
 
-    pthread_t serv, work;
+    to = zmq_socket (context2, ZMQ_PULL);
+    assert (to);
+    rc = zmq_bind (to, "tcp://*:5560");
+    assert (rc == 0);
+
+    val = 0;
+    rc = zmq_setsockopt (to, ZMQ_LINGER, &val, sizeof(val));
+    assert (rc == 0);
+
+    // Create a socket pushing 
+    from = zmq_socket (context, ZMQ_PUSH);
+    assert (from);
+
+    val = 0;
+    rc = zmq_setsockopt (from, ZMQ_LINGER, &val, sizeof(val));
+    assert (rc == 0);
+    val = 1;
+    rc = zmq_setsockopt (from, ZMQ_DELAY_ATTACH_ON_CONNECT, &val, sizeof(val));
+    assert (rc == 0);
+
+    // Connect to the valid socket socket
+    rc = zmq_connect (from, "tcp://localhost:5560");
+    assert (rc == 0);
+    
+    // Allow connections to stabilise
+    zmq_sleep(1);
+    
+    // Send a message, should succeed
+    std::string message("message ");
+    rc = zmq_send (from, message.data(), message.size(), 0);
+    assert (rc >= 0);
+    
+    rc = zmq_close (to);
+    assert (rc == 0);
+    
+    rc = zmq_ctx_destroy(context2);
+    assert (rc == 0);
+    
+    // Give time to process disconnect
+    zmq_sleep(1);
+    
+    // Send a message, should fail
+    rc = zmq_send (from, message.data(), message.size(), ZMQ_DONTWAIT);
+    assert (rc == -1);
+    
+    context2 = zmq_ctx_new();
+    to = zmq_socket (context2, ZMQ_PULL);
+    assert (to);
+    rc = zmq_bind (to, "tcp://*:5560");
+    assert (rc == 0);
 
-    rc = pthread_create (&serv, NULL, server, NULL);
+    val = 0;
+    rc = zmq_setsockopt (to, ZMQ_LINGER, &val, sizeof(val));
+    assert (rc == 0);
+    
+    // Allow connections to stabilise
+    zmq_sleep(1);
+    
+    // After the reconnect, should succeed
+    rc = zmq_send (from, message.data(), message.size(), 0);
+    assert (rc >= 0);
+    
+    rc = zmq_close (to);
+    assert (rc == 0);
+    
+    rc = zmq_close (from);
     assert (rc == 0);
 
-    rc = pthread_create (&work, NULL, worker, NULL);
+    rc = zmq_ctx_destroy(context);
     assert (rc == 0);
     
-    pthread_exit(NULL);
+    rc = zmq_ctx_destroy(context2);
+    assert (rc == 0);
 }