Unit Test hitting UrlHelper extension method always fails to match route based on route name

Question

... but the same extension method works when the application itself is executing. The UrlHelper extension method itself looks like this:

    public static string CategoryLandingPage(this UrlHelper helper, string seoCategoryName)
    {
        return helper.RouteUrl("Category", new { area = "SoAndSo", controller = "SoAndSo", action = "Category", seoCategoryName = seoCategoryName }, "http");
    }

I register that particular route like this in my SoAndSoAreaRegistration class:

        context.MapRoute(
           "Category",
           "category/{seoCategoryName}",
           new { area = "SoAndSo", controller = "SoAndSo", action = "Category", seoCategoryName = string.Empty }
        );

... and I have dropped a breakpoint on that registration to ensure that it gets hit by the test runner, and it does.

When I run the test, I get an ArgumentException, "A route named 'Category' could not be found in the route collection. Parameter name: name".

My guess is that we do not need to specify the route name and enough route parameters (area/controller/action/category name) to construct the route in its entirety as we're doing here, but I can't figure out where the route name disappears to during testing. Removing the category name eliminates the exception and allows the test to pass, but I would still like to understand where the route name disappears to when I'm testing. Simplifying the code like so still blows up at runtime:

    public static string CategoryLandingPage(this UrlHelper helper, string seoCategoryName)
    {
        return helper.RouteUrl("Category");            
    }

If I dig through the route collection at runtime, I can find the category route, but there is no evidence of a .Name property, nor do I see the route's name ("Category" with a capital C) anywhere among the UrlHelper's properties (apologies for the goofy obfuscation; better safe than sorry):

Does anyone know how I can write unit tests which hit UrlHelper extension methods which reference routes by their name? Thanks!

• Update - I'll add some of the test initialization, most of which I got from this popular question, lightly modified to account for the fact that the application I'm working with is separated into multiple MVC areas:

  private SoAndSoController CreateController() { var service = new Mock(); var cookieMgr = new Mock(); var logger = new Mock();

  var allRoutes = new RouteCollection();
  MvcApplication.RegisterRoutes(allRoutes);
  var soAndSoAreaRegistration = new SoAndSoAreaRegistration();
  var soAndSoAreaRegistrationContext = new AreaRegistrationContext(soAndSoAreaRegistration.AreaName, new RouteCollection());
  soAndSoAreaRegistration.RegisterArea(soAndSoAreaRegistrationContext);
  soAndSoAreaRegistrationContext.Routes.ForEach(r => allRoutes.Add(r));
  
  var request = new Mock<HttpRequestBase>();
  request.SetupGet(x => x.ApplicationPath).Returns("/");
  request.SetupGet(x => x.Url).Returns(new Uri("http://localhost/a", UriKind.Absolute));
  request.SetupGet(x => x.ServerVariables).Returns(new System.Collections.Specialized.NameValueCollection());
  
  var response = new Mock<HttpResponseBase>();
  response.Setup(x => x.ApplyAppPathModifier("/post1")).Returns("http://localhost/post1");
  
  var context = new Mock<HttpContextBase>();
  context.SetupGet(x => x.Request).Returns(request.Object);
  context.SetupGet(x => x.Response).Returns(response.Object);
  
  var controller = new SoAndSoController(service.Object, cookieMgr.Object, null, logger.Object, null);
  controller.ControllerContext = new ControllerContext(context.Object, new RouteData(), controller);
  controller.Url = new UrlHelper(new RequestContext(context.Object, new RouteData()), allRoutes);
  
  return controller;
  

  }

Answer 1

I figured it out. I needed to pass my RouteCollection into the AreaRegistrationContext, rather than passing it a new RouteCollection:

            var productFindingAreaRegistrationContext = new AreaRegistrationContext(productFindingAreaRegistration.AreaName, allRoutes);

But that was causing this line to blow up:

productFindingAreaRegistrationContext.Routes.ForEach(r => allRoutes.Add(r));

However now this line was no longer needed, so I commented it out. Voila.