public void ShouldNotThrowOnValidSitemapUrl()
        {
            var builder = new RobotsTxtOptionsBuilder();

            Should.NotThrow(() => builder.AddSitemap("https://example.com/sitemap.xml"));
        }
        public void ShouldThrowOnInvalidSitemapUrl(string url)
        {
            var builder = new RobotsTxtOptionsBuilder();

            Should.Throw <ArgumentException>(() => builder.AddSitemap(url));
        }