test: add negative cache ttl integration tests for implicit-dirs

changes.md

@@ -0,0 +1,23 @@
+# Changes for Negative Cache TTL on Implicit Directories
+
+## Summary
+
+Added integration test coverage to verify that the negative stat cache correctly respects the negative TTL configuration when handling implicit directories in gcsfuse.
+
+## Details
+
+1. **New Integration Test File:**
+   - Created `tools/integration_tests/negative_stat_cache/implicit_dir_finite_negative_stat_cache_test.go`
+   - Added `implicitDirFiniteNegativeStatCacheTest` suite testing the `--implicit-dirs` behavior alongside finite negative stat cache configuration.
+   - The test asserts that checking an implicit directory when it doesn't exist successfully populates the negative stat cache.
+   - It simulates an implicit directory creation by adding an object behind the scenes and ensures it remains unseen (due to negative stat cache) until the 5-second TTL expires.
+
+2. **Configuration Updates:**
+   - Appended a new `ConfigItem` within `tools/integration_tests/negative_stat_cache/setup_test.go` for the negative stat cache tests.
+   - The configuration runs the newly added test suite (`TestImplicitDirFiniteNegativeStatCacheTest`) with the flags `{"--metadata-cache-negative-ttl-secs=5", "--implicit-dirs"}`.
+   - Set the compatibility configuration parameter `hns` to `false` because Hierarchical Namespace (HNS) buckets do not conceptually support implicit directories.
+
+## Validation
+
+- Verified that all unit tests correctly pass using `go test ./...`
+- Specifically executed and successfully passed the added integration test with `go test ./tools/integration_tests/negative_stat_cache/... -run TestImplicitDirFiniteNegativeStatCacheTest`.

tools/integration_tests/negative_stat_cache/implicit_dir_finite_negative_stat_cache_test.go

@@ -0,0 +1,110 @@
+// Copyright 2025 Google LLC
+//
+// 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 negative_stat_cache
+
+import (
+	"log"
+	"os"
+	"path"
+	"testing"
+	"time"
+
+	"github.com/googlecloudplatform/gcsfuse/v3/tools/integration_tests/util/client"
+	"github.com/googlecloudplatform/gcsfuse/v3/tools/integration_tests/util/setup"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+)
+
+type implicitDirFiniteNegativeStatCacheTest struct {
+	flags   []string
+	testDir string
+	suite.Suite
+}
+
+func (s *implicitDirFiniteNegativeStatCacheTest) SetupSuite() {
+	setup.MountGCSFuseWithGivenMountWithConfigFunc(testEnv.cfg, s.flags, testEnv.mountFunc)
+	setup.SetMntDir(testEnv.mountDir)
+}
+
+func (s *implicitDirFiniteNegativeStatCacheTest) TearDownSuite() {
+	setup.UnmountGCSFuseWithConfig(testEnv.cfg)
+}
+
+func (s *implicitDirFiniteNegativeStatCacheTest) SetupTest() {
+	s.testDir = testDirName + setup.GenerateRandomString(5)
+	testEnv.testDirPath = setup.SetupTestDirectory(s.testDir)
+}
+
+func (s *implicitDirFiniteNegativeStatCacheTest) TearDownTest() {
+	setup.SaveGCSFuseLogFileInCaseOfFailure(s.T())
+}
+
+////////////////////////////////////////////////////////////////////////
+// Test scenarios
+////////////////////////////////////////////////////////////////////////
+
+func (s *implicitDirFiniteNegativeStatCacheTest) TestImplicitDirFiniteNegativeStatCache() {
+	targetDir := path.Join(testEnv.testDirPath, "implicit_dir")
+
+	// Error should be returned as the implicit directory doesn't exist
+	_, err := os.Stat(targetDir)
+
+	assert.NotNil(s.T(), err)
+	// Assert the underlying error is File Not Exist
+	assert.ErrorContains(s.T(), err, "no such file or directory")
+
+	// Adding an object inside the path to create an implicit directory
+	client.CreateObjectInGCSTestDir(testEnv.ctx, testEnv.storageClient, s.testDir, path.Join("implicit_dir", "file1.txt"), "some-content", s.T())
+
+	// Error should be returned again, as call will not be served from GCS due to finite gcsfuse stat cache
+	_, err = os.Stat(targetDir)
+
+	assert.NotNil(s.T(), err)
+	// Assert the underlying error is File Not Exist
+	assert.ErrorContains(s.T(), err, "no such file or directory")
+
+	//Wait for Cache to expire
+	time.Sleep(5 * time.Second)
+
+	// Directory should be returned, as call will be served from GCS and gcsfuse should not return from cache
+	fileInfo, err := os.Stat(targetDir)
+
+	//Assert Directory is found and it is a directory
+	assert.NoError(s.T(), err)
+	assert.True(s.T(), fileInfo.IsDir())
+}
+
+////////////////////////////////////////////////////////////////////////
+// Test Function (Runs once before all tests)
+////////////////////////////////////////////////////////////////////////
+
+func TestImplicitDirFiniteNegativeStatCacheTest(t *testing.T) {
+	ts := &implicitDirFiniteNegativeStatCacheTest{}
+
+	// Run tests for mounted directory if the flag is set.
+	if testEnv.cfg.GKEMountedDirectory != "" && testEnv.cfg.TestBucket != "" {
+		suite.Run(t, ts)
+		return
+	}
+
+	// Define flag set to run the tests.
+	flagsSet := setup.BuildFlagSets(*testEnv.cfg, testEnv.bucketType, t.Name())
+
+	// Run tests.
+	for _, ts.flags = range flagsSet {
+		log.Printf("Running tests with flags: %s", ts.flags)
+		suite.Run(t, ts)
+	}
+}

tools/integration_tests/negative_stat_cache/setup_test.go

@@ -73,7 +73,7 @@ func TestMain(m *testing.M) {
 		cfg.NegativeStatCache[0].GKEMountedDirectory = setup.MountedDirectory()
 		cfg.NegativeStatCache[0].LogFile = setup.LogFile()
 		// Initialize the slice to hold specific test configurations
-		cfg.NegativeStatCache[0].Configs = make([]test_suite.ConfigItem, 3)
+		cfg.NegativeStatCache[0].Configs = make([]test_suite.ConfigItem, 4)
 		cfg.NegativeStatCache[0].Configs[0].Flags = []string{"--metadata-cache-negative-ttl-secs=0"}
 		cfg.NegativeStatCache[0].Configs[0].Compatible = map[string]bool{"flat": true, "hns": true, "zonal": true}
 		cfg.NegativeStatCache[0].Configs[0].Run = "TestDisabledNegativeStatCacheTest"
@@ -83,6 +83,9 @@ func TestMain(m *testing.M) {
 		cfg.NegativeStatCache[0].Configs[2].Flags = []string{"--metadata-cache-negative-ttl-secs=-1"}
 		cfg.NegativeStatCache[0].Configs[2].Compatible = map[string]bool{"flat": true, "hns": true, "zonal": true}
 		cfg.NegativeStatCache[0].Configs[2].Run = "TestInfiniteNegativeStatCacheTest"
+		cfg.NegativeStatCache[0].Configs[3].Flags = []string{"--metadata-cache-negative-ttl-secs=5", "--implicit-dirs"}
+		cfg.NegativeStatCache[0].Configs[3].Compatible = map[string]bool{"flat": true, "hns": false, "zonal": true}
+		cfg.NegativeStatCache[0].Configs[3].Run = "TestImplicitDirFiniteNegativeStatCacheTest"
 	}
 
 	testEnv.ctx = context.Background()