[NPM] Fix recent unit test failures from each controller (#880)

* Use sharedInformer for only local storage to cache resource to make deterministic unit tests

* add comments in the codes

* add comments for future enhancement for unit tests

Author: JungukCho

npm/nameSpaceController_test.go

@@ -70,8 +70,9 @@ func (f *nameSpaceFixture) newNsController(stopCh chan struct{}) {
 	for _, ns := range f.nsLister {
 		f.kubeInformer.Core().V1().Namespaces().Informer().GetIndexer().Add(ns)
 	}
-
-	f.kubeInformer.Start(stopCh)
+	// Do not start informer to avoid unnecessary event triggers.
+	// (TODO) Leave stopCh and below commented code to enhance UTs to even check event triggers as well later if possible
+	//f.kubeInformer.Start()
 }
 
 func (f *nameSpaceFixture) ipSetSave(ipsetConfigFile string) {

npm/networkPolicyController_test.go

@@ -78,7 +78,9 @@ func (f *netPolFixture) newNetPolController(stopCh chan struct{}) {
 		f.kubeInformer.Networking().V1().NetworkPolicies().Informer().GetIndexer().Add(netPol)
 	}
 
-	f.kubeInformer.Start(stopCh)
+	// Do not start informer to avoid unnecessary event triggers
+	// (TODO): Leave stopCh and below commented code to enhance UTs to even check event triggers as well later if possible
+	//f.kubeInformer.Start(stopCh)
 }
 
 func (f *netPolFixture) saveIpTables(iptablesConfigFile string) {

npm/podController_test.go

@@ -67,7 +67,9 @@ func (f *podFixture) newPodController(stopCh chan struct{}) {
 		f.kubeInformer.Core().V1().Pods().Informer().GetIndexer().Add(pod)
 	}
 
-	f.kubeInformer.Start(stopCh)
+	// Do not start informer to avoid unnecessary event triggers
+	// (TODO): Leave stopCh and below commented code to enhance UTs to even check event triggers as well later if possible
+	//f.kubeInformer.Start(stopCh)
 }
 
 func (f *podFixture) ipSetSave(ipsetConfigFile string) {