Unit test asp.net route mapping extension method

I have an extension class for Routes. I want to test the updated list of routecollection. This is an extract:

public static void MapMyRoutes(this RouteCollection routes)
{
    //do some stuff
    routes.MapHttpRoute(null, controllerPath.Path, new { @namespace = controllerPath.Namespace, controller = controllerPath.ControllerName, id = UrlParameter.Optional });
}

I want to unit test this extension, but can't work out how to extract the mapped url from the routecollection:

This is a test:

[TestMethod]
public void TestMapMyRoutesMapsCorrectly()
{
    var routes = new RouteCollection();
    routes.MapMyRoutes();

    foreach (var route in routes)
    {
        Assert.AreEqual(route.??, "v1/api/myRoute");
    }
}