private static void AssertCanGetRoutingPages(IVirtualFiles vfs, Action fn = null)
        {
            Files.ForEach(vfs.WriteFile);

            foreach (var entry in Expected)
            {
                entry.Key.Print();
                var html = Config.ListeningOn.CombineWith(entry.Key).GetStringFromUrl(accept: MimeTypes.Html);
                Assert.That(html.NormalizeNewLines(), Is.EqualTo(entry.Value));
            }

            fn?.Invoke();
        }