Add unit tests for OnRemove (#473)

* Add unit tests for OnRemove

* Address review comment

pkg/generic/remove_test.go

@@ -0,0 +1,119 @@
+package generic
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+func Test_objectLifecycleAdapter_sync(t *testing.T) {
+	const handlerName = "test"
+	type args struct {
+		key string
+		obj runtime.Object
+	}
+	tests := []struct {
+		name             string
+		args             args
+		wantErr          bool
+		wantFunc         func(runtime.Object) error
+		wantHandlerCount int
+		wantUpdaterCount int
+	}{
+		{
+			name: "nil object",
+			args: args{
+				"objectkey", nil,
+			},
+			wantFunc: func(obj runtime.Object) error {
+				if obj != nil {
+					return fmt.Errorf("obj should be nil")
+				}
+				return nil
+			},
+		},
+		{
+			name: "new object",
+			args: args{
+				"test/service", &corev1.Service{
+					ObjectMeta: metav1.ObjectMeta{Namespace: "test", Name: "service"},
+				},
+			},
+			wantUpdaterCount: 1, // update to add finalizer
+		},
+		{
+			name: "existing object with finalizer",
+			args: args{
+				"test/service", &corev1.Service{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "test", Name: "service",
+						Finalizers: []string{"finalizer", finalizerKey + handlerName},
+					},
+				},
+			},
+			wantUpdaterCount: 0, // finalizer already set, no need to update
+		},
+		{
+			name: "deleted object with finalizer",
+			args: args{
+				key: "test/service", obj: &corev1.Service{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "test", Name: "service",
+						Finalizers:        []string{"finalizer", finalizerKey + handlerName},
+						DeletionTimestamp: &metav1.Time{Time: time.Now()},
+					},
+				},
+			},
+			wantHandlerCount: 1,
+			wantUpdaterCount: 1, // update removing finalizer
+		},
+		{
+			name: "deleted object without finalizer",
+			args: args{
+				key: "test/service", obj: &corev1.Service{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: "test", Name: "service",
+						DeletionTimestamp: &metav1.Time{Time: time.Now()},
+					},
+				},
+			},
+			wantHandlerCount: 0,
+			wantUpdaterCount: 0,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var handlerCount, updaterCount int
+			updater := func(obj runtime.Object) (runtime.Object, error) {
+				updaterCount++
+				return obj, nil
+			}
+			handler := func(key string, obj runtime.Object) (runtime.Object, error) {
+				handlerCount++
+				return obj, nil
+			}
+
+			sync := NewRemoveHandler("test", updater, handler)
+			got, err := sync(tt.args.key, tt.args.obj)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("sync() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if tt.wantFunc != nil {
+				if err := tt.wantFunc(got); err != nil {
+					t.Errorf("sync() unexpected value = %v, err: %v", got, err)
+				}
+			}
+			if handlerCount != tt.wantHandlerCount {
+				t.Errorf("handlerCount = %v, want %v", handlerCount, tt.wantHandlerCount)
+			}
+			if updaterCount != tt.wantUpdaterCount {
+				t.Errorf("updaterCount = %v, want %v", updaterCount, tt.wantUpdaterCount)
+			}
+		})
+	}
+}