assertEquals("DataService is null. IndexUpdater cannot proceed without a DataService instance.", e.getMessage());
        }
    }

    // Test run method basic flow
    @Test
    public void test_run_basicFlow() throws Exception {
        final List<String> sessionIdList = Arrays.asList("session1");
        indexUpdater.setSessionIdList(sessionIdList);

        final CountDownLatch latch = new CountDownLatch(1);