### Question:
JsonRpc2_0Geth extends JsonRpc2_0Admin implements Geth { @Override public Observable<SyncingNotfication> syncingStatusNotifications() { return web3jService.subscribe( new Request<>( "eth_subscribe", Arrays.asList("syncing"), web3jService, PlatonSubscribe.class), "eth_unsubscribe", SyncingNotfication.class ); } JsonRpc2_0Geth(Web3jService web3jService); @Override Request<?, PersonalImportRawKey> personalImportRawKey(
            String keydata, String password); @Override Request<?, BooleanResponse> personalLockAccount(String accountId); @Override Request<?, PersonalSign> personalSign(
            String message, String accountId, String password); @Override Request<?, PersonalEcRecover> personalEcRecover(
            String hexMessage, String signedMessage); @Override Request<?, MinerStartResponse> minerStart(int threadCount); @Override Request<?, BooleanResponse> minerStop(); Observable<PendingTransactionNotification> newPendingTransactionsNotifications(); @Override Observable<SyncingNotfication> syncingStatusNotifications();  }### Answer:
@Test public void testSyncingStatusNotifications() { geth.syncingStatusNotifications(); verify(webSocketClient).send(matches( "\\{\"jsonrpc\":\"2.0\",\"method\":\"eth_subscribe\"," + "\"params\":\\[\"syncing\"],\"id\":[0-9]{1,}}")); }