Ensure proper serialization of updates and creates in federation test watcher

federation/pkg/federation-controller/util/test/test_helper.go

@@ -39,8 +39,10 @@ import (
 // A structure that distributes eventes to multiple watchers.
 type WatcherDispatcher struct {
 	sync.Mutex
-	watchers    []*watch.RaceFreeFakeWatcher
-	eventsSoFar []*watch.Event
+	watchers       []*watch.RaceFreeFakeWatcher
+	eventsSoFar    []*watch.Event
+	orderExecution chan func()
+	stopChan       chan struct{}
 }
 
 func (wd *WatcherDispatcher) register(watcher *watch.RaceFreeFakeWatcher) {
@@ -55,6 +57,7 @@ func (wd *WatcherDispatcher) register(watcher *watch.RaceFreeFakeWatcher) {
 func (wd *WatcherDispatcher) Stop() {
 	wd.Lock()
 	defer wd.Unlock()
+	close(wd.stopChan)
 	for _, watcher := range wd.watchers {
 		watcher.Stop()
 	}
@@ -136,9 +139,21 @@ func (wd *WatcherDispatcher) Action(action watch.EventType, obj runtime.Object)
 // All subsequent requests for a watch on the client will result in returning this fake watcher.
 func RegisterFakeWatch(resource string, client *core.Fake) *WatcherDispatcher {
 	dispatcher := &WatcherDispatcher{
-		watchers:    make([]*watch.RaceFreeFakeWatcher, 0),
-		eventsSoFar: make([]*watch.Event, 0),
+		watchers:       make([]*watch.RaceFreeFakeWatcher, 0),
+		eventsSoFar:    make([]*watch.Event, 0),
+		orderExecution: make(chan func()),
+		stopChan:       make(chan struct{}),
 	}
+	go func() {
+		for {
+			select {
+			case fun := <-dispatcher.orderExecution:
+				fun()
+			case <-dispatcher.stopChan:
+				return
+			}
+		}
+	}()
 
 	client.AddWatchReactor(resource, func(action core.Action) (bool, watch.Interface, error) {
 		watcher := watch.NewRaceFreeFake()
@@ -166,11 +181,11 @@ func RegisterFakeCopyOnCreate(resource string, client *core.Fake, watcher *Watch
 		originalObj := createAction.GetObject()
 		// Create a copy of the object here to prevent data races while reading the object in go routine.
 		obj := copy(originalObj)
-		go func() {
+		watcher.orderExecution <- func() {
 			glog.V(4).Infof("Object created. Writing to channel: %v", obj)
 			watcher.Add(obj)
 			objChan <- obj
-		}()
+		}
 		return true, originalObj, nil
 	})
 	return objChan
@@ -186,11 +201,11 @@ func RegisterFakeCopyOnUpdate(resource string, client *core.Fake, watcher *Watch
 		originalObj := updateAction.GetObject()
 		// Create a copy of the object here to prevent data races while reading the object in go routine.
 		obj := copy(originalObj)
-		go func() {
+		watcher.orderExecution <- func() {
 			glog.V(4).Infof("Object updated. Writing to channel: %v", obj)
 			watcher.Modify(obj)
 			objChan <- obj
-		}()
+		}
 		return true, originalObj, nil
 	})
 	return objChan