defer

func ReturnErr() error {
	return errors.New("hello")
}

func DeferErr() error {
	return errors.New("deferred")
}

func HandleErrs() error {
	var err error
	defer func() {
		err = DeferErr()
		if err != nil {
			fmt.Println("deferred" + err.Error())
		}
	}()
	err = ReturnErr()
	if err != nil {
		return err
	}
	return nil
}

func TestDeferErr(t *testing.T) {
	err := HandleErrs()
	if err != nil {
		t.Error("the big one" + err.Error())
	}
}