mirror of https://github.com/grpc/grpc-go.git
54 lines
1.4 KiB
Go
54 lines
1.4 KiB
Go
/*
|
|
*
|
|
* 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)
|
|
}
|
|
}
|