assertNull(result, "getAnchorSet should return null for whitespace string");
    }

    /**
     * Test getAnchorSet with list of URLs
     */
    @Test
    public void test_getAnchorSet_withList() {
        FessCrawlerThread crawlerThread = new FessCrawlerThread();

        List<String> urls = new ArrayList<>();
        urls.add("http://example.com/page1");
        urls.add("http://example.com/page2");