54 lines
800 B
Go
54 lines
800 B
Go
package once
|
|
|
|
import (
|
|
"testing"
|
|
)
|
|
|
|
type one int
|
|
|
|
func (o *one) Increment() {
|
|
*o++
|
|
}
|
|
|
|
func run(t *testing.T, once *Once, o *one, c chan bool) {
|
|
once.Do(func() { o.Increment() })
|
|
if v := *o; v != 1 {
|
|
t.Errorf("once failed inside run: %d is not 1", v)
|
|
}
|
|
c <- true
|
|
}
|
|
|
|
func TestOnce(t *testing.T) {
|
|
o := new(one)
|
|
once := New()
|
|
c := make(chan bool)
|
|
const N = 10
|
|
for i := 0; i < N; i++ {
|
|
go run(t, once, o, c)
|
|
}
|
|
for i := 0; i < N; i++ {
|
|
<-c
|
|
}
|
|
if *o != 1 {
|
|
t.Errorf("once failed outside run: %d is not 1", *o)
|
|
}
|
|
}
|
|
|
|
func TestOncePanic(t *testing.T) {
|
|
once := New()
|
|
|
|
func() {
|
|
defer func() {
|
|
if r := recover(); r == nil {
|
|
t.Fatalf("Once.Do did not panic")
|
|
}
|
|
}()
|
|
once.Do(func() {
|
|
panic("failed")
|
|
})
|
|
}()
|
|
|
|
once.Do(func() {
|
|
t.Fatalf("Once.Do called twice")
|
|
})
|
|
}
|