fix test issue

pkg/kernelmonitor/kernel_log_watcher.go

@@ -168,15 +168,10 @@ func (k *kernelLogWatcher) watchLoop() {
 
 // getLogReader gets a kernel log reader.
 func getLogReader(path string) (io.Reader, error) {
-	reader, err := tryJournal()
-	if err == nil {
-		return reader, nil
+	if len(path) != 0 {
+		return tryLogFile(path)
 	}
-	reader, err = tryLogFile(path)
-	if err == nil {
-		return reader, nil
-	}
-	return nil, err
+	return tryJournal()
 }
 
 func tryJournal() (io.Reader, error) {
@@ -205,6 +200,7 @@ func tryLogFile(path string) (io.Reader, error) {
 		return nil, err
 	}
 	glog.Infof("Kernel log watcher use log file: %s", path)
+	time.Sleep(1000 * time.Millisecond)
 	return tail, nil
 }
 

pkg/kernelmonitor/kernel_log_watcher_test.go

@@ -100,13 +100,15 @@ func TestWatch(t *testing.T) {
 			t.Fatal(err)
 		}
 		defer func() {
-			f.Close()
 			os.Remove(f.Name())
 		}()
 		_, err = f.Write([]byte(test.log))
 		if err != nil {
 			t.Fatal(err)
 		}
+
+		f.Close()
+	
 		w := NewKernelLogWatcher(WatcherConfig{KernelLogPath: f.Name(), Lookback: test.lookback})
 		// Set the fake clock.
 		w.(*kernelLogWatcher).clock = fakeClock