Move util to specific package location

pkg/util/file/file_watcher_test.go

@@ -0,0 +1,138 @@
+/*
+Copyright 2015 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 file
+
+import (
+	"os"
+	"path"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func prepareTimeout() chan bool {
+	timeoutChan := make(chan bool, 1)
+	go func() {
+		time.Sleep(500 * time.Millisecond)
+		timeoutChan <- true
+	}()
+	return timeoutChan
+}
+
+func TestFileWatcher(t *testing.T) {
+	f, err := os.CreateTemp("", "fw")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer f.Close()
+	defer os.Remove(f.Name())
+	count := 0
+	events := make(chan bool, 10)
+	fw, err := NewFileWatcher(f.Name(), func() {
+		count++
+		if count != 1 {
+			t.Fatalf("expected 1 but returned %v", count)
+		}
+		events <- true
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer fw.Close()
+	timeoutChan := prepareTimeout()
+	select {
+	case <-events:
+		t.Fatalf("expected no events before writing a file")
+	case <-timeoutChan:
+	}
+	os.WriteFile(f.Name(), []byte{}, ReadWriteByUser)
+	select {
+	case <-events:
+	case <-timeoutChan:
+		t.Fatalf("expected an event shortly after writing a file")
+	}
+}
+
+func TestFileWatcherWithNestedSymlink(t *testing.T) {
+	target1, err := os.CreateTemp("", "t1")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer target1.Close()
+	defer os.Remove(target1.Name())
+	dir := path.Dir(target1.Name())
+
+	innerLink := path.Join(dir, "innerLink")
+	if err = os.Symlink(target1.Name(), innerLink); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer os.Remove(innerLink)
+	mainLink := path.Join(dir, "mainLink")
+	if err = os.Symlink(innerLink, mainLink); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer os.Remove(mainLink)
+
+	targetName, err := filepath.EvalSymlinks(mainLink)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if targetName != target1.Name() {
+		t.Fatalf("expected symlink to point to %v, not %v", target1.Name(), targetName)
+	}
+
+	count := 0
+	events := make(chan bool, 10)
+	fw, err := NewFileWatcher(mainLink, func() {
+		count++
+		if count != 1 {
+			t.Fatalf("expected 1 but returned %v", count)
+		}
+		if targetName, err = filepath.EvalSymlinks(mainLink); err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		events <- true
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer fw.Close()
+
+	target2, err := os.CreateTemp("", "t2")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	defer target2.Close()
+	defer os.Remove(target2.Name())
+
+	if err = os.Remove(innerLink); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if err = os.Symlink(target2.Name(), innerLink); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	timeoutChan := prepareTimeout()
+	select {
+	case <-events:
+	case <-timeoutChan:
+		t.Fatalf("expected an event shortly after creating a file and relinking")
+	}
+	if targetName != target2.Name() {
+		t.Fatalf("expected symlink to point to %v, not %v", target2.Name(), targetName)
+	}
+}