message: [miner]fix miner_test.
diff: use actix_rt::System;
  use bus::BusActor;
  -use chain::{ChainActor, ChainActorRef};
  +use chain::{ChainActor, ChainActorRef, SyncMetadata};
  use config::{NodeConfig, PacemakerStrategy};
  use consensus::dummy::DummyConsensus;
  use consensus::dummy::DummyHeader;
  @@ -56,6 +56,7 @@ fn test_miner_with_schedule_pacemaker() {
  )
  };
  let network = NetworkActor::launch(config.clone(), bus.clone(), handle.clone());
  + let sync_metadata = SyncMetadata::new(config.clone());
  let chain = ChainActor::launch(
  config.clone(),
  startup_info.clone(),
  @@ -63,6 +64,7 @@ fn test_miner_with_schedule_pacemaker() {
  Some(network.clone()),
  bus.clone(),
  txpool.clone(),
  + sync_metadata.clone(),
  )
  .unwrap();
  let miner_account = WalletAccount::random();
  @@ -99,6 +101,7 @@ fn test_miner_with_schedule_pacemaker() {
  network.clone(),
  bus.clone(),
  storage.clone(),
  + sync_metadata.clone(),
  )
  .expect("launch DownloadActor failed.");
  let _sync = SyncActor::launch(bus.clone(), process_actor, download_actor).unwrap();
  @@ -145,6 +148,7 @@ fn test_miner_with_ondemand_pacemaker() {
  )
  };
  let network = NetworkActor::launch(config.clone(), bus.clone(), handle.clone());
  + let sync_metadata = SyncMetadata::new(config.clone());
  let chain = ChainActor::launch(
  config.clone(),
  startup_info.clone(),
  @@ -152,6 +156,7 @@ fn test_miner_with_ondemand_pacemaker() {
  Some(network.clone()),
  bus.clone(),
  txpool.clone(),
  + sync_metadata.clone(),
  )
  .unwrap();
  let receiver = txpool.clone().subscribe_txns().await.unwrap();
  @@ -189,6 +194,7 @@ fn test_miner_with_ondemand_pacemaker() {
  network.clone(),
  bus.clone(),
  storage.clone(),
  + sync_metadata.clone(),
  )
  .expect("launch DownloadActor failed.");
  let _sync = SyncActor::launch(bus.clone(), process_actor, download_actor).unwrap();
  