assertEquals(0, docList.size());
        assertEquals(2, sentDocList.size());
        assertEquals("fess.update", sentIndex.get());
    }

    @Test
    public void test_deleteOldDocuments() {
        documentSizeByQuery = 0L;
        final List<String> deletedDocIdList = new ArrayList<>();
        final List<Map<String, Object>> oldDocList = new ArrayList<>();