libgo/misc/cgo/test/issue1560.go

   1 // Copyright 2011 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 cgotest
   6
   7 /*
   8 // mysleep returns the absolute start time in ms.
   9 long long mysleep(int seconds);
  10
  11 // twoSleep returns the absolute start time of the first sleep
  12 // in ms.
  13 long long twoSleep(int);
  14 */
  15 import "C"
  16
  17 import (
  18         "testing"
  19         "time"
  20 )
  21
  22 var sleepDone = make(chan int64)
  23
  24 // parallelSleep returns the absolute difference between the start time
  25 // of the two sleeps.
  26 func parallelSleep(n int) int64 {
  27         t := int64(C.twoSleep(C.int(n))) - <-sleepDone
  28         if t < 0 {
  29                 return -t
  30         }
  31         return t
  32 }
  33
  34 //export BackgroundSleep
  35 func BackgroundSleep(n int32) {
  36         go func() {
  37                 sleepDone <- int64(C.mysleep(C.int(n)))
  38         }()
  39 }
  40
  41 func testParallelSleep(t *testing.T) {
  42         sleepSec := 1
  43         dt := time.Duration(parallelSleep(sleepSec)) * time.Millisecond
  44         t.Logf("difference in start time for two sleep(%d) is %v", sleepSec, dt)
  45         // bug used to run sleeps in serial, producing a 2*sleepSec-second delay.
  46         // we detect if the start times of those sleeps are > 0.5*sleepSec-second.
  47         if dt >= time.Duration(sleepSec)*time.Second/2 {
  48                 t.Fatalf("parallel %d-second sleeps slept for %f seconds", sleepSec, dt.Seconds())
  49         }
  50 }