blob: 2b0db8d3eaa3a26c8ab30aa6b92d4e17f9ac2bf6 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
/*
*
* Copyright 2022 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package grpcsync
import (
"sync"
"sync/atomic"
"testing"
"time"
)
// TestOnceFunc tests that a OnceFunc is executed only once even with multiple
// simultaneous callers of it.
func (s) TestOnceFunc(t *testing.T) {
var v int32
inc := OnceFunc(func() { atomic.AddInt32(&v, 1) })
const numWorkers = 100
var wg sync.WaitGroup // Blocks until all workers have called inc.
wg.Add(numWorkers)
block := NewEvent() // Signal to worker goroutines to call inc
for i := 0; i < numWorkers; i++ {
go func() {
<-block.Done() // Wait for a signal.
inc() // Call the OnceFunc.
wg.Done()
}()
}
time.Sleep(time.Millisecond) // Allow goroutines to get to the block.
block.Fire() // Unblock them.
wg.Wait() // Wait for them to complete.
if v != 1 {
t.Fatalf("OnceFunc() called %v times; want 1", v)
}
}
|
