problem: timers test is flapping on windows

tests/test_timers.cpp

@@ -46,6 +46,19 @@ void handler (int timer_id, void* arg)
     *((bool *)arg) = true;
 }
 
+int sleep_and_execute(void *timers_) 
+{
+    int timeout = zmq_timers_timeout (timers_);
+
+    //  Sleep methods are inaccurate, so we sleep in a loop until time arrived
+    while (timeout > 0) {
+        sleep_ (timeout);
+        timeout = zmq_timers_timeout(timers_);
+    }
+
+    return zmq_timers_execute(timers_);
+}
+
 int main (void)
 {
     setup_test_environment ();
@@ -70,8 +83,7 @@ int main (void)
     assert (!timer_invoked);
 
     // Wait until the end    
-    sleep_ (zmq_timers_timeout (timers));
-    rc = zmq_timers_execute (timers);
+    rc = sleep_and_execute (timers);
     assert (rc == 0);
     assert (timer_invoked);
     timer_invoked = false;
@@ -91,16 +103,14 @@ int main (void)
     assert (!timer_invoked);
 
     // Wait until the end
-    sleep_ (zmq_timers_timeout (timers));
-    rc = zmq_timers_execute (timers);
+    rc = sleep_and_execute(timers);
     assert (rc == 0);
     assert (timer_invoked);
     timer_invoked = false;
 
     // reschedule
     zmq_timers_set_interval (timers, timer_id, 50);
-    sleep_ (51);
-    rc = zmq_timers_execute (timers);
+    rc = sleep_and_execute(timers);
     assert (rc == 0);
     assert (timer_invoked);
     timer_invoked = false;