Kernel List Cache: Composite Test (#2036)

* Added simple cache hit/miss test

* Added cache related test, remaining: refactoring and with different operation

* pushing the internal changes

* Refactoring for basic test

* Fixing lint issue

* some cleaning

* review comments

* pushing missed file

* Rebase

* review comments

internal/fs/fs_test.go

@@ -249,6 +249,10 @@ func (t *fsTest) createObjects(in map[string]string) error {
 	return err
 }
 
+func (t *fsTest) deleteObject(name string) error {
+	return bucket.DeleteObject(ctx, &gcs.DeleteObjectRequest{Name: name})
+}
+
 func (t *fsTest) createEmptyObjects(names []string) error {
 	err := storageutil.CreateEmptyObjects(ctx, bucket, names)
 	return err

internal/fs/kernel_list_cache_inifinite_ttl_test.go

@@ -0,0 +1,88 @@
+// Copyright 2024 Google Inc. All Rights Reserved.
+//
+// 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.
+
+// Please refer kernel_list_cache_test.go for the documentation.
+
+package fs_test
+
+import (
+	"os"
+	"path"
+	"testing"
+	"time"
+
+	"github.com/googlecloudplatform/gcsfuse/v2/internal/config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+)
+
+type KernelListCacheTestWithInfiniteTtl struct {
+	suite.Suite
+	fsTest
+	KernelListCacheTestCommon
+}
+
+func (t *KernelListCacheTestWithInfiniteTtl) SetupSuite() {
+	t.serverCfg.ImplicitDirectories = true
+	t.serverCfg.MountConfig = &config.MountConfig{
+		FileSystemConfig: config.FileSystemConfig{
+			KernelListCacheTtlSeconds: -1,
+		},
+		MetadataCacheConfig: config.MetadataCacheConfig{
+			TtlInSeconds: 0,
+		},
+	}
+	t.serverCfg.RenameDirLimit = 10
+	t.fsTest.SetUpTestSuite()
+}
+
+func TestKernelListCacheTestInfiniteTtlSuite(t *testing.T) {
+	suite.Run(t, new(KernelListCacheTestWithInfiniteTtl))
+}
+
+// (a) First ReadDir() will be served from GCSFuse filesystem.
+// (b) Second ReadDir() will also be served from GCSFuse filesystem.
+func (t *KernelListCacheTestWithInfiniteTtl) TestKernelListCache_AlwaysCacheHit() {
+	// First read, kernel will cache the dir response.
+	f, err := os.Open(path.Join(mntDir, "explicitDir"))
+	assert.Nil(t.T(), err)
+	defer func() {
+		assert.Nil(t.T(), f.Close())
+	}()
+	names1, err := f.Readdirnames(-1)
+	assert.Nil(t.T(), err)
+	require.Equal(t.T(), 2, len(names1))
+	assert.Equal(t.T(), "file1.txt", names1[0])
+	assert.Equal(t.T(), "file2.txt", names1[1])
+	err = f.Close()
+	assert.Nil(t.T(), err)
+	// Adding one object to make sure to change the ReadDir() response.
+	assert.Nil(t.T(), t.createObjects(map[string]string{
+		"explicitDir/file3.txt": "123456",
+	}))
+	defer t.deleteObjectOrFail("explicitDir/file3.txt")
+	// Advancing time by 5 years (157800000 seconds).
+	cacheClock.AdvanceTime(157800000 * time.Second)
+
+	// No invalidation since infinite ttl.
+	f, err = os.Open(path.Join(mntDir, "explicitDir"))
+	assert.Nil(t.T(), err)
+	names2, err := f.Readdirnames(-1)
+
+	assert.Nil(t.T(), err)
+	require.Equal(t.T(), 2, len(names2))
+	assert.Equal(t.T(), "file1.txt", names2[0])
+	assert.Equal(t.T(), "file2.txt", names2[1])
+}