@Override
    public String toString() {
        return "Transaction{"
                + "txnId='" + txnId + '\''
                + ", state=" + state
                + ", txType=" + transactionType
                + ", timeoutMillis=" + timeoutMillis
                + '}';
    }
@Test
    public void testToString() throws Exception {
        TransactionImpl tx = new TransactionImpl(txManagerService, nodeEngine, options, UUID.randomUUID());
        assertEquals(format("Transaction{txnId='%s', state=%s, txType=%s, timeoutMillis=%s}",
                tx.getTxnId(), tx.getState(), options.getTransactionType(), options.getTimeoutMillis()), tx.toString());
    }