@Test
    public void test_render_bold() {
        String result = markdownRenderer.render("**bold text**");
        assertTrue(result.contains("<strong>bold text</strong>"));
    }

    @Test
    public void test_render_italic() {
        String result = markdownRenderer.render("*italic text*");
        assertTrue(result.contains("italic text"));
    }

    @Test
    public void test_render_heading1() {