Problem: test_reqrep_tcp does not test multiple endpoints

Solution: add a test for this use case

tests/test_reqrep_tcp.cpp

@@ -62,11 +62,82 @@ void test_single_connect_ipv4 (void)
     assert (rc == 0);
 }
 
+void test_multi_connect_ipv4 (void)
+{
+    void *ctx = zmq_ctx_new ();
+    assert (ctx);
+
+    void *sb0 = zmq_socket (ctx, ZMQ_REP);
+    assert (sb0);
+    int rc = zmq_bind (sb0, "tcp://127.0.0.1:5560");
+    assert (rc == 0);
+
+    void *sb1 = zmq_socket (ctx, ZMQ_REP);
+    assert (sb1);
+    rc = zmq_bind (sb1, "tcp://127.0.0.1:5561");
+    assert (rc == 0);
+
+    void *sb2 = zmq_socket (ctx, ZMQ_REP);
+    assert (sb2);
+    rc = zmq_bind (sb2, "tcp://127.0.0.1:5562");
+    assert (rc == 0);
+
+    void *sc = zmq_socket (ctx, ZMQ_REQ);
+    assert (sc);
+    rc = zmq_connect (sc, "tcp://127.0.0.1:5560");
+    assert (rc == 0);
+    rc = zmq_connect (sc, "tcp://127.0.0.1:5561");
+    assert (rc == 0);
+    rc = zmq_connect (sc, "tcp://127.0.0.1:5562");
+    assert (rc == 0);
+
+    bounce (sb0, sc);
+    bounce (sb1, sc);
+    bounce (sb2, sc);
+    bounce (sb0, sc);
+    bounce (sb1, sc);
+    bounce (sb2, sc);
+    bounce (sb0, sc);
+
+    rc = zmq_disconnect (sc, "tcp://127.0.0.1:5560");
+    assert (rc == 0);
+    rc = zmq_disconnect (sc, "tcp://127.0.0.1:5562");
+    assert (rc == 0);
+    rc = zmq_disconnect (sc, "tcp://127.0.0.1:5561");
+    assert (rc == 0);
+
+    rc = zmq_unbind (sb0, "tcp://127.0.0.1:5560");
+    assert (rc == 0);
+
+    rc = zmq_unbind (sb1, "tcp://127.0.0.1:5561");
+    assert (rc == 0);
+
+    rc = zmq_unbind (sb2, "tcp://127.0.0.1:5562");
+    assert (rc == 0);
+
+    rc = zmq_close (sc);
+    assert (rc == 0);
+
+    rc = zmq_close (sb0);
+    assert (rc == 0);
+
+    rc = zmq_close (sb1);
+    assert (rc == 0);
+
+    rc = zmq_close (sb2);
+    assert (rc == 0);
+
+    rc = zmq_ctx_term (ctx);
+    assert (rc == 0);
+}
+
 int main (void)
 {
     setup_test_environment ();
 
     test_single_connect_ipv4 ();
 
+    test_multi_connect_ipv4 ();
+
     return 0 ;
 }