crawlerContext.setRobotsTxtUrlSet(newSet);
        assertSame(newSet, crawlerContext.getRobotsTxtUrlSet());
        assertEquals(1, crawlerContext.getRobotsTxtUrlSet().size());

        // Set null
        crawlerContext.setRobotsTxtUrlSet(null);
        assertNull(crawlerContext.getRobotsTxtUrlSet());
    }

    /**
     * Test LRU behavior of robotsTxtUrlSet
     */

            CrawlingParameterUtil.setCrawlerContext(crawlerContext);
            httpClient.init();
            httpClient.processRobotsTxt(url);
            assertEquals(1, crawlerContext.getRobotsTxtUrlSet().size());
            assertTrue(crawlerContext.getRobotsTxtUrlSet().contains("http://localhost:7070/robots.txt"));
            assertFalse(urlFilter.match("http://localhost:7070/admin/"));

        this.intervalController = intervalController;
    }

    /**
     * Returns the set of robots.txt URLs.
     * @return The set of robots.txt URLs.
     */
    public Set<String> getRobotsTxtUrlSet() {
        return robotsTxtUrlSet;
    }

    /**
     * Sets the set of robots.txt URLs.
     * @param robotsTxtUrlSet The set of robots.txt URLs.
     */

        } else {
            hostUrl = url;
        }
        final String robotTxtUrl = hostUrl + "/robots.txt";

        // check url
        if (crawlerContext.getRobotsTxtUrlSet().contains(robotTxtUrl)) {
            if (logger.isDebugEnabled()) {
                logger.debug("{} is already visited.", robotTxtUrl);
            }
            return;
        }