public PendingTransactionFilter(Web3j web3j, Callback<String> callback) {
        super(web3j, callback);
    }
@Test
    public void testPendingTransactionFilter() throws Exception {
        EthLog ethLog =
                objectMapper.readValue(
                        "{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":[\"0x31c2342b1e0b8ffda1507fbffddf213c4b3c1e819ff6a84b943faabb0ebf2403\",\"0xccc0d2e07c1febcaca0c3341c4e1268204b06fefa4bb0c8c0d693d8e581c82da\"]}",
                        EthLog.class);

        runTest(ethLog, web3j.ethPendingTransactionHashFlowable());
    }