cacher: Move common testing utils to a single file

This commit prepares for when cacher tests are moved here
from the `tests` package. Tests in that package redeclare
some of the testing utils that exist here, so dedup-ing them.

This commit also adapts to any changes in test util signatures.
There are still some utils that can be reused but currently are
highly specific to some tests. (ex: watch_cache_test.go)

Signed-off-by: Madhav Jivrajani <madhav.jiv@gmail.com>

staging/src/k8s.io/apiserver/pkg/storage/cacher/cacher_testing_utils_test.go

@@ -0,0 +1,78 @@
+/*
+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 cacher
+
+import (
+	"fmt"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/apitesting"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apiserver/pkg/apis/example"
+	examplev1 "k8s.io/apiserver/pkg/apis/example/v1"
+	example2v1 "k8s.io/apiserver/pkg/apis/example2/v1"
+	"k8s.io/apiserver/pkg/storage"
+	"k8s.io/apiserver/pkg/storage/etcd3"
+	etcd3testing "k8s.io/apiserver/pkg/storage/etcd3/testing"
+	storagetesting "k8s.io/apiserver/pkg/storage/testing"
+	"k8s.io/apiserver/pkg/storage/value/encrypt/identity"
+)
+
+var (
+	scheme   = runtime.NewScheme()
+	codecs   = serializer.NewCodecFactory(scheme)
+	errDummy = fmt.Errorf("dummy error")
+)
+
+func init() {
+	metav1.AddToGroupVersion(scheme, metav1.SchemeGroupVersion)
+	utilruntime.Must(example.AddToScheme(scheme))
+	utilruntime.Must(examplev1.AddToScheme(scheme))
+	utilruntime.Must(example2v1.AddToScheme(scheme))
+}
+
+func newPod() runtime.Object     { return &example.Pod{} }
+func newPodList() runtime.Object { return &example.PodList{} }
+
+func newEtcdTestStorage(t *testing.T, prefix string, pagingEnabled bool) (*etcd3testing.EtcdTestServer, storage.Interface) {
+	server, _ := etcd3testing.NewUnsecuredEtcd3TestClientServer(t)
+	storage := etcd3.New(
+		server.V3Client,
+		apitesting.TestCodec(codecs, examplev1.SchemeGroupVersion),
+		newPod,
+		prefix,
+		schema.GroupResource{Resource: "pods"},
+		identity.NewEncryptCheckTransformer(),
+		pagingEnabled,
+		etcd3.NewDefaultLeaseManagerConfig())
+	return server, storage
+}
+
+func makeTestPodWithName(name string) *example.Pod {
+	return &example.Pod{
+		ObjectMeta: metav1.ObjectMeta{Namespace: "ns", Name: name},
+		Spec:       storagetesting.DeepEqualSafePodSpec(),
+	}
+}
+
+func computePodKey(obj *example.Pod) string {
+	return fmt.Sprintf("/pods/%s/%s", obj.Namespace, obj.Name)
+}

staging/src/k8s.io/apiserver/pkg/storage/cacher/cacher_whitebox_test.go

@@ -38,8 +38,6 @@ import (
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
-	"k8s.io/apimachinery/pkg/runtime/serializer"
-	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/apiserver/pkg/apis/example"
@@ -51,25 +49,11 @@ import (
 	etcd3testing "k8s.io/apiserver/pkg/storage/etcd3/testing"
 	"k8s.io/apiserver/pkg/storage/value/encrypt/identity"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
-	utilflowcontrol "k8s.io/apiserver/pkg/util/flowcontrol"
 	featuregatetesting "k8s.io/component-base/featuregate/testing"
 	"k8s.io/utils/clock"
 	"k8s.io/utils/pointer"
 )
 
-var (
-	scheme   = runtime.NewScheme()
-	codecs   = serializer.NewCodecFactory(scheme)
-	errDummy = fmt.Errorf("dummy error")
-)
-
-func init() {
-	metav1.AddToGroupVersion(scheme, metav1.SchemeGroupVersion)
-	utilruntime.Must(example.AddToScheme(scheme))
-	utilruntime.Must(examplev1.AddToScheme(scheme))
-	utilruntime.Must(example2v1.AddToScheme(scheme))
-}
-
 func newTestCacher(s storage.Interface) (*Cacher, storage.Versioner, error) {
 	prefix := "pods"
 	config := Config{
@@ -312,7 +296,7 @@ func TestWatchCacheBypass(t *testing.T) {
 }
 
 func TestEmptyWatchEventCache(t *testing.T) {
-	server, etcdStorage := newEtcdTestStorage(t, etcd3testing.PathPrefix())
+	server, etcdStorage := newEtcdTestStorage(t, etcd3testing.PathPrefix(), true)
 	defer server.Terminate(t)
 
 	// add a few objects
@@ -762,27 +746,6 @@ func TestCacherNoLeakWithMultipleWatchers(t *testing.T) {
 	}
 }
 
-func TestWatchInitializationSignal(t *testing.T) {
-	backingStorage := &dummyStorage{}
-	cacher, _, err := newTestCacher(backingStorage)
-	if err != nil {
-		t.Fatalf("Couldn't create cacher: %v", err)
-	}
-	defer cacher.Stop()
-
-	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-	defer cancel()
-	initSignal := utilflowcontrol.NewInitializationSignal()
-	ctx = utilflowcontrol.WithInitializationSignal(ctx, initSignal)
-
-	_, err = cacher.Watch(ctx, "pods/ns", storage.ListOptions{ResourceVersion: "0", Predicate: storage.Everything})
-	if err != nil {
-		t.Fatalf("Failed to create watch: %v", err)
-	}
-
-	initSignal.Wait()
-}
-
 func testCacherSendBookmarkEvents(t *testing.T, allowWatchBookmarks, expectedBookmarks bool) {
 	backingStorage := &dummyStorage{}
 	cacher, _, err := newTestCacher(backingStorage)

staging/src/k8s.io/apiserver/pkg/storage/cacher/lister_watcher_test.go

@@ -18,44 +18,17 @@ package cacher
 
 import (
 	"context"
-	"fmt"
 	"testing"
 
-	"k8s.io/apimachinery/pkg/api/apitesting"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apiserver/pkg/apis/example"
-	examplev1 "k8s.io/apiserver/pkg/apis/example/v1"
-	"k8s.io/apiserver/pkg/storage"
-	"k8s.io/apiserver/pkg/storage/etcd3"
-	etcd3testing "k8s.io/apiserver/pkg/storage/etcd3/testing"
-	"k8s.io/apiserver/pkg/storage/value/encrypt/identity"
 )
 
-func newPod() runtime.Object { return &example.Pod{} }
-
-func computePodKey(obj *example.Pod) string {
-	return fmt.Sprintf("/pods/%s/%s", obj.Namespace, obj.Name)
-}
-
-func newEtcdTestStorage(t *testing.T, prefix string) (*etcd3testing.EtcdTestServer, storage.Interface) {
-	server, _ := etcd3testing.NewUnsecuredEtcd3TestClientServer(t)
-	storage := etcd3.New(
-		server.V3Client,
-		apitesting.TestCodec(codecs, examplev1.SchemeGroupVersion),
-		newPod, prefix,
-		schema.GroupResource{Resource: "pods"},
-		identity.NewEncryptCheckTransformer(),
-		true,
-		etcd3.NewDefaultLeaseManagerConfig())
-	return server, storage
-}
-
 func TestCacherListerWatcher(t *testing.T) {
 	prefix := "pods"
 	fn := func() runtime.Object { return &example.PodList{} }
-	server, store := newEtcdTestStorage(t, prefix)
+	server, store := newEtcdTestStorage(t, prefix, true)
 	defer server.Terminate(t)
 
 	objects := []*example.Pod{
@@ -89,7 +62,7 @@ func TestCacherListerWatcher(t *testing.T) {
 func TestCacherListerWatcherPagination(t *testing.T) {
 	prefix := "pods"
 	fn := func() runtime.Object { return &example.PodList{} }
-	server, store := newEtcdTestStorage(t, prefix)
+	server, store := newEtcdTestStorage(t, prefix, true)
 	defer server.Terminate(t)
 
 	// We need the list to be sorted by name to later check the alphabetical order of