}
    }

    /**
     * Test isEmpty() check on deleteUrlList with concurrent access.
     * This simulates the check in commit() method.
     */
    @Test
    public void test_deleteUrlList_isEmptyCheck() throws Exception {
        IndexUpdateCallback mockCallback = new IndexUpdateCallback() {
            @Override
            public void store(DataStoreParams paramMap, Map<String, Object> dataMap) {