layer1: prepare managed namespace watchers

pkg/utils/namespace_manager_test.go

@@ -429,6 +429,25 @@ func TestNewNamespaceWatcherEventHandlers(t *testing.T) {
 	}
 }
 
+func TestPrepareManagedNamespaceWatcher(t *testing.T) {
+	router := &testNamespaceSubscriber{name: "router"}
+	logger := zap.NewNop()
+	manager, handlers, err := PrepareManagedNamespaceWatcher(context.Background(), logger, "router.NSWatcher", []string{"tenant-a"}, NamespaceRemovalStrategyTrackOnly, router)
+	if err != nil {
+		t.Fatalf("expected watcher preparation success: %v", err)
+	}
+	if !reflect.DeepEqual([]string{"tenant-a"}, manager.Snapshot()) {
+		t.Fatalf("expected watcher manager snapshot to contain bootstrapped namespace")
+	}
+	namespace := &corev1.Namespace{}
+	namespace.Name = "tenant-a"
+	namespace.Labels = map[string]string{ManagedNamespaceLabelKey: ManagedNamespaceLabelValue}
+	handlers.UpdateFunc(namespace, namespace)
+	if router.addCalls != 1 || router.resyncCalls != 1 {
+		t.Fatalf("expected bootstrap add and handler resync calls")
+	}
+}
+
 func TestNamespaceManagerDispatchAdd(t *testing.T) {
 	manager := NewNamespaceManager()
 	manager.Upsert(NamespaceEvent{Type: NamespaceEventAdd, Name: "tenant-a", Source: NamespaceSourceWatcher})