82 lines
1.4 KiB
Go
82 lines
1.4 KiB
Go
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package waitgroup
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import (
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"sync/atomic"
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"testing"
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)
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func testWaitGroup(t *testing.T, wg1 *WaitGroup, wg2 *WaitGroup) {
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n := 16
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wg1.Add(n)
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wg2.Add(n)
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exited := make(chan bool, n)
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for i := 0; i != n; i++ {
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go func() {
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wg1.Done()
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wg2.Wait()
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exited <- true
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}()
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}
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wg1.Wait()
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for i := 0; i != n; i++ {
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select {
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case <-exited:
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t.Fatal("WaitGroup released group too soon")
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default:
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}
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wg2.Done()
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}
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for i := 0; i != n; i++ {
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<-exited // Will block if barrier fails to unlock someone.
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}
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}
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func TestWaitGroup(t *testing.T) {
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wg1 := New()
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wg2 := New()
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// Run the same test a few times to ensure barrier is in a proper state.
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for i := 0; i != 8; i++ {
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testWaitGroup(t, wg1, wg2)
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}
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}
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func TestWaitGroupMisuse(t *testing.T) {
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defer func() {
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err := recover()
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if err != "negative WaitGroup counter" {
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t.Fatalf("Unexpected panic: %#v", err)
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}
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}()
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wg := New()
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wg.Add(1)
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wg.Done()
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wg.Done()
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t.Fatal("Should panic")
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}
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func TestWaitGroupRace(t *testing.T) {
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// Run this test for about 1ms.
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for i := 0; i < 1000; i++ {
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wg := New()
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n := new(int32)
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// spawn goroutine 1
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wg.Add(1)
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go func() {
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atomic.AddInt32(n, 1)
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wg.Done()
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}()
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// spawn goroutine 2
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wg.Add(1)
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go func() {
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atomic.AddInt32(n, 1)
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wg.Done()
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}()
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// Wait for goroutine 1 and 2
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wg.Wait()
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if atomic.LoadInt32(n) != 2 {
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t.Fatal("Spurious wakeup from Wait")
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}
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}
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}
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