*
     * @param config the crawling configuration containing time-to-live settings
     * @return the document expiration date, or null if no expiration is set
     */
    public Date getDocumentExpires(final CrawlingConfig config) {
        if (config != null) {
            final Integer timeToLive = config.getTimeToLive();
            if (timeToLive != null) {
                // timeToLive minutes

            assertEquals("No crawling session.", e.getMessage());
        }
    }

    public void test_getDocumentExpires() {
        // Test with null config
        assertNull(crawlingInfoHelper.getDocumentExpires(null));

        // Test with documentExpires field set (fallback behavior)
        final long currentTime = 1704067200000L; // 2024-01-01 00:00:00 UTC
        ComponentUtil.register(new SystemHelper() {

        final CrawlingInfoHelper crawlingInfoHelper = ComponentUtil.getCrawlingInfoHelper();
        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        final Date documentExpires = crawlingInfoHelper.getDocumentExpires(config);
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final Map<String, String> paramEnvMap = systemHelper.getFilteredEnvMap(fessConfig.getCrawlerDataEnvParamKeyPattern());

        final PathMappingHelper pathMappingHelper = ComponentUtil.getPathMappingHelper();
        final Date documentExpires = crawlingInfoHelper.getDocumentExpires(crawlingConfig);
        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        final FileTypeHelper fileTypeHelper = ComponentUtil.getFileTypeHelper();

                    storeChildUrlsToQueue(urlQueue, getAnchorSet(document.get(fessConfig.getIndexFieldAnchor())));

                    final Date documentExpires = crawlingInfoHelper.getDocumentExpires(crawlingConfig);
                    if (documentExpires != null
                            && !indexingHelper.updateDocument(searchEngineClient, id, fessConfig.getIndexFieldExpires(), documentExpires)) {

        final PathMappingHelper pathMappingHelper = ComponentUtil.getPathMappingHelper();
        final CrawlingConfig crawlingConfig = getCrawlingConfig(responseData);
        final Date documentExpires = crawlingInfoHelper.getDocumentExpires(crawlingConfig);
        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        final FileTypeHelper fileTypeHelper = ComponentUtil.getFileTypeHelper();