package main

import "fmt"

type testEnum int

const (
    test0 testEnum = iota
    test1
    test2
    test3
)

func (t testEnum) String() string {
    switch t {
    case test0:
        return "test0"
    case test1:
        return "test1"
    case test2:
        return "test2"
    case test3:
        return "test3"
    default:
        return fmt.Sprintf("testEnum(%d)", int(t))
    }
}

func main() {
    fmt.Println(struct{ a testEnum }{a: test1})
}