blob: f551d790a4fda9d03993219168ca2bc23c2e1e72 [file] [log] [blame]
// 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) {
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) {
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) {
var g Group
c := make(chan string)
var calls int32
fn := func() (interface{}, error) {
atomic.AddInt32(&calls, 1)
return <-c, nil
}
const n = 10
var wg sync.WaitGroup
for i := 0; i < n; i++ {
wg.Add(1)
go func() {
v, err, _ := g.Do("key", fn)
if err != nil {
t.Errorf("Do error: %v", err)
}
if v.(string) != "bar" {
t.Errorf("got %q; want %q", v, "bar")
}
wg.Done()
}()
}
time.Sleep(100 * time.Millisecond) // let goroutines above block
c <- "bar"
wg.Wait()
if got := atomic.LoadInt32(&calls); got != 1 {
t.Errorf("number of calls = %d; want 1", got)
}
}