assertFalse(registration.isExpired(60000));
    
    // Test sequence numbers
    long seq1 = registration.getNextSequenceNumber();
    long seq2 = registration.getNextSequenceNumber();
    assertEquals(seq1 + 1, seq2);
}

@Test
public void testWitnessNotification() {
    WitnessNotification notification = new WitnessNotification(

        try {
            WitnessHeartbeatRequest request = new WitnessHeartbeatRequest();
            request.setRegistrationId(registration.getRegistrationId());
            request.setSequenceNumber(registration.getNextSequenceNumber());

            WitnessHeartbeatResponse response = rpcClient.heartbeat(request);

            if (response != null && response.isSuccess()) {
                registration.updateHeartbeat();