WitnessRegisterResponse mockResponse = mock(WitnessRegisterResponse.class);
        lenient().when(mockResponse.isSuccess()).thenReturn(true);
        lenient().when(mockResponse.getRegistrationId()).thenReturn("test-reg-123");

        WitnessRpcClient mockRpc = mock(WitnessRpcClient.class);
        lenient().when(mockRpc.register(any(WitnessRegisterRequest.class))).thenReturn(mockResponse);

        this.lastHeartbeat = registrationTime;
        this.flags = WITNESS_REGISTER_IP_NOTIFICATION;
    }
    
    private String generateRegistrationId() {
        return "REG-" + System.currentTimeMillis() + "-" + 
               Integer.toHexString(System.identityHashCode(this));
    }
    
    public long getNextSequenceNumber() {
        return sequenceNumber.incrementAndGet();
    }