libgo/go/sync/once_test.go

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package sync_test
   6
   7 import (
   8         . "sync"
   9         "testing"
  10 )
  11
  12 type one int
  13
  14 func (o *one) Increment() {
  15         *o++
  16 }
  17
  18 func run(once *Once, o *one, c chan bool) {
  19         once.Do(func() { o.Increment() })
  20         c <- true
  21 }
  22
  23 func TestOnce(t *testing.T) {
  24         o := new(one)
  25         once := new(Once)
  26         c := make(chan bool)
  27         const N = 10
  28         for i := 0; i < N; i++ {
  29                 go run(once, o, c)
  30         }
  31         for i := 0; i < N; i++ {
  32                 <-c
  33         }
  34         if *o != 1 {
  35                 t.Errorf("once failed: %d is not 1", *o)
  36         }
  37 }