func testBlockEpochNotification(miner *rpctest.Harness,
notifier chainntnfs.ChainNotifier, t *testing.T) {
// We'd like to test the case of multiple registered clients receiving
// block epoch notifications.
const numBlocks = 10
const numClients = 5
var wg sync.WaitGroup
// Create numClients clients which will listen for block notifications. We
// expect each client to receive 10 notifications for each of the ten
// blocks we generate below. So we'll use a WaitGroup to synchronize the
// test.
for i := 0; i < numClients; i++ {
epochClient, err := notifier.RegisterBlockEpochNtfn()
if err != nil {
t.Fatalf("unable to register for epoch notification")
}
wg.Add(numBlocks)
go func() {
for i := 0; i < numBlocks; i++ {
<-epochClient.Epochs
wg.Done()
}
}()
}
epochsSent := make(chan struct{})
go func() {
wg.Wait()
close(epochsSent)
}()
// Now generate 10 blocks, the clients above should each receive 10
// notifications, thereby unblocking the goroutine above.
if _, err := miner.Node.Generate(numBlocks); err != nil {
t.Fatalf("unable to generate blocks: %v", err)
}
select {
case <-epochsSent:
case <-time.After(2 * time.Second):
t.Fatalf("all notifications not sent")
}
}
