for (Thread th : threads) {
            th.join();
        }
        assertEquals(num * 2, count.get());
        assertEquals(num, valueSet2.size());
    }

    @Test
    public void test_getLimitDocNum() throws Exception {
        assertEquals(10, ESSourceReader.getLimitDocNum(100, 10, -1));
        assertEquals(25, ESSourceReader.getLimitDocNum(50, 50, -1));