decouple system namespaces from bootstrap controller

Use an informer instead of polling.

Change-Id: Ib071e53addb914fcb31d8a1346cf61ca6d22520b

pkg/controlplane/controller/systemnamespaces/system_namespaces_controller_test.go

@@ -0,0 +1,144 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package systemnamespaces
+
+import (
+	"testing"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes/fake"
+	k8stesting "k8s.io/client-go/testing"
+	"k8s.io/gengo/examples/set-gen/sets"
+)
+
+// Test_Controller validates the garbage collection logic for the apiserverleasegc controller.
+func Test_Controller(t *testing.T) {
+	systemNamespaces := []string{metav1.NamespaceSystem, metav1.NamespacePublic, v1.NamespaceNodeLease}
+
+	tests := []struct {
+		name       string
+		namespaces []string
+		actions    [][]string // verb and resource
+	}{
+		{
+			name: "no system namespaces",
+			actions: [][]string{
+				{"create", "namespaces"},
+				{"create", "namespaces"},
+				{"create", "namespaces"},
+			},
+		},
+		{
+			name:       "no system namespaces but others",
+			namespaces: []string{"foo", "bar"},
+			actions: [][]string{
+				{"create", "namespaces"},
+				{"create", "namespaces"},
+				{"create", "namespaces"},
+			},
+		},
+		{
+			name:       "one system namespace",
+			namespaces: []string{metav1.NamespaceSystem},
+			actions: [][]string{
+				{"create", "namespaces"},
+				{"create", "namespaces"},
+			},
+		},
+		{
+			name:       "two system namespaces",
+			namespaces: []string{metav1.NamespaceSystem, metav1.NamespacePublic},
+			actions: [][]string{
+				{"create", "namespaces"},
+			},
+		},
+
+		{
+			name:       "the three namespaces",
+			namespaces: []string{metav1.NamespaceSystem, metav1.NamespacePublic, v1.NamespaceNodeLease},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			objs := []runtime.Object{}
+			for _, ns := range test.namespaces {
+				objs = append(objs,
+					&v1.Namespace{
+						ObjectMeta: metav1.ObjectMeta{
+							Name:      ns,
+							Namespace: "",
+						},
+					},
+				)
+			}
+			clientset := fake.NewSimpleClientset(objs...)
+			informerFactory := informers.NewSharedInformerFactory(clientset, 0)
+			namespaceInformer := informerFactory.Core().V1().Namespaces()
+			for _, obj := range objs {
+				namespaceInformer.Informer().GetIndexer().Add(obj)
+			}
+
+			controller := NewController(clientset, namespaceInformer)
+
+			clientset.PrependReactor("create", "namespaces", func(action k8stesting.Action) (bool, runtime.Object, error) {
+				create := action.(k8stesting.CreateAction)
+				namespaceInformer.Informer().GetIndexer().Add(create.GetObject())
+				return true, create.GetObject(), nil
+			})
+
+			controller.sync()
+
+			expectAction(t, clientset.Actions(), test.actions)
+			namespaces, err := controller.namespaceLister.List(labels.Everything())
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+
+			got := sets.NewString()
+			for _, ns := range namespaces {
+				got.Insert(ns.Name)
+			}
+
+			if !got.HasAll(systemNamespaces...) {
+				t.Errorf("unexpected namespaces: %v", got.List())
+			}
+		})
+	}
+}
+
+func expectAction(t *testing.T, actions []k8stesting.Action, expected [][]string) {
+	t.Helper()
+	if len(actions) != len(expected) {
+		t.Fatalf("Expected at least %d actions, got %d", len(expected), len(actions))
+	}
+
+	for i, action := range actions {
+		verb := expected[i][0]
+		if action.GetVerb() != verb {
+			t.Errorf("Expected action %d verb to be %s, got %s", i, verb, action.GetVerb())
+		}
+		resource := expected[i][1]
+		if action.GetResource().Resource != resource {
+			t.Errorf("Expected action %d resource to be %s, got %s", i, resource, action.GetResource().Resource)
+		}
+	}
+}