repo/common/logger.gopackage commonvar once sync.Oncevar Logger *logrus.Loggerfunc InitLogger() {   once.Do(func() {        Logger = logrus.New()        Logger.Out = filename // file opened and *file assigned here for logging    })    return Logger}回購/setup_test.gopackage mainfunc setUp() {    common.InitLogger()    fmt.Println(common.Logger) // prints some pointer related things which means logger is initialized}func TestMain(m *testing.M) {    fmt.Println("Starting Test...")    setUp()    code := m.Run()    common.APILog.Println("Finishing Main...")    os.Exit(code)}回購/車輛/品牌/maruti/car/mycar_test.gopackage carfunc TestMyFunc(t *testing.T) {    **t.Log(common.Logger)               // When i run go test ./... this Prints nil , Why ?**    // Doing some tests}由于這個 common.Logger.Println("some data") 到處都給出零指針錯誤根據我的理解，一旦 Logger 被初始化，它應該是可用的，因為它是一個全局變量。我肯定在這里遺漏了一些微妙的東西。請幫忙