@Mock
    private MemoryDataHelper dataHelper;

    @Override
    protected void setUp() throws Exception {
        super.setUp();
        MockitoAnnotations.openMocks(this);
    }

    public void test_add() {
        // Setup
        String sessionId = "session123";
        String url = "https://example.com/page";
        Queue<UrlQueueImpl<Long>> mockQueue = new LinkedList<>();