public void optional_asset()
        {
            thePage.OptionalAsset("a.js", "b.css");

            theRequirements.AssertWasCalled(x => x.UseAssetIfExists("a.js", "b.css"));
        }
 /// <summary>
 /// Registers an asset for the current request *if* it can be found.
 /// </summary>
 /// <param name="page"></param>
 /// <param name="scripts"></param>
 public static void OptionalScript(this IFubuPage page, params string[] scripts)
 {
     page.OptionalAsset(scripts);
 }