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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package singleflight
import (
"errors"
"fmt"
"sync"
"sync/atomic"
"testing"
"time"
)
func TestDo(t *testing.T) {
t.Skip("singleflight tests not stable")
var g Group
v, err, _ := g.Do("key", func() (interface{}, error) {
return "bar", nil
})
if got, want := fmt.Sprintf("%v (%T)", v, v), "bar (string)"; got != want {
t.Errorf("Do = %v; want %v", got, want)
}
if err != nil {
t.Errorf("Do error = %v", err)
}
}
func TestDoErr(t *testing.T) {
t.Skip("singleflight tests not stable")
var g Group
someErr := errors.New("Some error")
v, err, _ := g.Do("key", func() (interface{}, error) {
return nil, someErr
})
if err != someErr {
t.Errorf("Do error = %v; want someErr %v", err, someErr)
}
if v != nil {
t.Errorf("unexpected non-nil value %#v", v)
}
}
func TestDoDupSuppress(t *testing.T) {
t.Skip("singleflight tests not stable")
var g Group
var wg1, wg2 sync.WaitGroup
c := make(chan string, 1)
var calls int32
fn := func() (interface{}, error) {
if atomic.AddInt32(&calls, 1) == 1 {
// First invocation.
wg1.Done()
}
v := <-c
c <- v // pump; make available for any future calls
time.Sleep(10 * time.Millisecond) // let more goroutines enter Do
return v, nil
}
const n = 10
wg1.Add(1)
for i := 0; i < n; i++ {
wg1.Add(1)
wg2.Add(1)
go func() {
defer wg2.Done()
wg1.Done()
v, err, _ := g.Do("key", fn)
if err != nil {
t.Errorf("Do error: %v", err)
return
}
if s, _ := v.(string); s != "bar" {
t.Errorf("Do = %T %v; want %q", v, v, "bar")
}
}()
}
wg1.Wait()
// At least one goroutine is in fn now and all of them have at
// least reached the line before the Do.
c <- "bar"
wg2.Wait()
if got := atomic.LoadInt32(&calls); got <= 0 || got >= n {
t.Errorf("number of calls = %d; want over 0 and less than %d", got, n)
}
}
// Test that singleflight behaves correctly after Forget called.
// See https://github.com/golang/go/issues/31420
func TestForget(t *testing.T) {
t.Skip("singleflight tests not stable")
var g Group
var firstStarted, firstFinished sync.WaitGroup
firstStarted.Add(1)
firstFinished.Add(1)
firstCh := make(chan struct{})
go func() {
g.Do("key", func() (i interface{}, e error) {
firstStarted.Done()
<-firstCh
firstFinished.Done()
return
})
}()
firstStarted.Wait()
g.Forget("key") // from this point no two function using same key should be executed concurrently
var secondStarted int32
var secondFinished int32
var thirdStarted int32
secondCh := make(chan struct{})
secondRunning := make(chan struct{})
go func() {
g.Do("key", func() (i interface{}, e error) {
defer func() {
}()
atomic.AddInt32(&secondStarted, 1)
// Notify that we started
secondCh <- struct{}{}
// Wait other get above signal
<-secondRunning
<-secondCh
atomic.AddInt32(&secondFinished, 1)
return 2, nil
})
}()
close(firstCh)
firstFinished.Wait() // wait for first execution (which should not affect execution after Forget)
<-secondCh
// Notify second that we got the signal that it started
secondRunning <- struct{}{}
if atomic.LoadInt32(&secondStarted) != 1 {
t.Fatal("Second execution should be executed due to usage of forget")
}
if atomic.LoadInt32(&secondFinished) == 1 {
t.Fatal("Second execution should be still active")
}
close(secondCh)
result, _, _ := g.Do("key", func() (i interface{}, e error) {
atomic.AddInt32(&thirdStarted, 1)
return 3, nil
})
if atomic.LoadInt32(&thirdStarted) != 0 {
t.Error("Third call should not be started because was started during second execution")
}
if result != 2 {
t.Errorf("We should receive result produced by second call, expected: 2, got %d", result)
}
}
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