From d12072a23a97e309eccf8596cde34343fdd55244 Mon Sep 17 00:00:00 2001
From: Geon-Ju Kim <geonju42@gmail.com>
Date: Mon, 8 Mar 2021 09:56:51 +0900
Subject: [PATCH] kubelet_test: Deflake TestWatchFileChanged

- Adjust the period to trigger PodUpdate event
- Fix lock race between 'changeFile' and 'expectUpdate'
- Await fsnotify to be ready
---
 pkg/kubelet/config/file_linux_test.go | 38 +++++++++++++++------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/pkg/kubelet/config/file_linux_test.go b/pkg/kubelet/config/file_linux_test.go
index 2c1c0018cd7..e3cab80ea49 100644
--- a/pkg/kubelet/config/file_linux_test.go
+++ b/pkg/kubelet/config/file_linux_test.go
@@ -108,11 +108,16 @@ var (
 	testCases = []struct {
 		watchDir bool
 		symlink  bool
+		period   time.Duration
 	}{
-		{true, true},
-		{true, false},
-		{false, true},
-		{false, false},
+		// set the period to be long enough for the file to be changed
+		// and short enough to trigger the event
+		{true, true, 3 * time.Second},
+
+		// set the period to avoid periodic PodUpdate event
+		{true, false, 60 * time.Second},
+		{false, true, 60 * time.Second},
+		{false, false, 60 * time.Second},
 	}
 )
 
@@ -124,7 +129,7 @@ func TestWatchFileAdded(t *testing.T) {
 
 func TestWatchFileChanged(t *testing.T) {
 	for _, testCase := range testCases {
-		watchFileChanged(testCase.watchDir, testCase.symlink, t)
+		watchFileChanged(testCase.watchDir, testCase.symlink, testCase.period, t)
 	}
 }
 
@@ -275,7 +280,7 @@ func watchFileAdded(watchDir bool, symlink bool, t *testing.T) {
 	}
 }
 
-func watchFileChanged(watchDir bool, symlink bool, t *testing.T) {
+func watchFileChanged(watchDir bool, symlink bool, period time.Duration, t *testing.T) {
 	hostname := types.NodeName("random-test-hostname")
 	var testCases = getTestCases(hostname)
 
@@ -314,22 +319,23 @@ func watchFileChanged(watchDir bool, symlink bool, t *testing.T) {
 			}()
 
 			if watchDir {
-				NewSourceFile(dirName, hostname, 100*time.Millisecond, ch)
+				NewSourceFile(dirName, hostname, period, ch)
 			} else {
-				NewSourceFile(file, hostname, 100*time.Millisecond, ch)
+				NewSourceFile(file, hostname, period, ch)
 			}
+
+			// await fsnotify to be ready
+			time.Sleep(time.Second)
+
 			// expect an update by SourceFile.resetStoreFromPath()
 			expectUpdate(t, ch, testCase)
 
+			pod := testCase.pod.(*v1.Pod)
+			pod.Spec.Containers[0].Name = "image2"
+
+			testCase.expected.Pods[0].Spec.Containers[0].Name = "image2"
 			changeFile := func() {
 				// Edit the file content
-				testCase.lock.Lock()
-				defer testCase.lock.Unlock()
-
-				pod := testCase.pod.(*v1.Pod)
-				pod.Spec.Containers[0].Name = "image2"
-
-				testCase.expected.Pods[0].Spec.Containers[0].Name = "image2"
 				if symlink {
 					file = testCase.writeToFile(linkedDirName, fileName, t)
 					return
@@ -374,8 +380,6 @@ func expectUpdate(t *testing.T, ch chan interface{}, testCase *testCase) {
 				}
 			}
 
-			testCase.lock.Lock()
-			defer testCase.lock.Unlock()
 			if !apiequality.Semantic.DeepEqual(testCase.expected, update) {
 				t.Fatalf("%s: Expected: %#v, Got: %#v", testCase.desc, testCase.expected, update)
 			}