assertTrue(error.contains("invalidOption"));
        } finally {
            System.setErr(originalErr);
        }
    }

    // Test doCrawl method
    @Test
    public void test_doCrawl_withAllNull() {
        Crawler.Options options = new Crawler.Options();
        options.sessionId = "test-session";

        int result = crawler.doCrawl(options);
        assertEquals(Constants.EXIT_OK, result);