thread2.start();

        thread1.join();
        thread2.join();

        // Should complete without errors
        assertNotNull(urlFilter);
    }

    /**
     * Test boundary conditions
     */
    public void test_boundaryConditions() {
        String sessionId = "test-session-024";
        urlFilter.init(sessionId);

        // Test empty pattern
        urlFilter.addInclude("");

        assertEquals("instance1", transformer1.getName());
        assertEquals("changed2", transformer2.getName());
        assertEquals("instance3", transformer3.getName());
    }

    /**
     * Test name boundary cases
     */
    public void test_name_boundaryCases() {
        // Single character
        testTransformer.setName("a");
        assertEquals("a", testTransformer.getName());

        // Single space

        assertEquals(100L, crawlerContext.getAccessCount());
        assertEquals(100, crawlerContext.getRobotsTxtUrlSet().size());
        assertNotNull(crawlerContext.removeSitemaps());
    }

    /**
     * Test boundary values
     */
    public void test_boundaryValues() {
        // Test with maximum values
        crawlerContext.setActiveThreadCount(Integer.MAX_VALUE);