ASP.NET MVC: Unit testing controllers that use UrlHelper

asp.net-mvc, unit-testing, urlhelper

Solution

Here is one of my tests (xUnit + Moq) just for similar case (using Url.RouteUrl in controller)

var routes = new RouteCollection();
MvcApplication.RegisterRoutes(routes);

var request = new Mock<HttpRequestBase>(MockBehavior.Strict);
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>(MockBehavior.Strict);
response.Setup(x => x.ApplyAppPathModifier("/post1")).Returns("http://localhost/post1");

var context = new Mock<HttpContextBase>(MockBehavior.Strict);
context.SetupGet(x => x.Request).Returns(request.Object);
context.SetupGet(x => x.Response).Returns(response.Object);

var controller = new LinkbackController(dbF.Object);
controller.ControllerContext = new ControllerContext(context.Object, new RouteData(), controller);
controller.Url = new UrlHelper(new RequestContext(context.Object, new RouteData()), routes);

Problem

One of my controllers actions, one that is being called in an Ajax request, is returning an URL to the client side so it can do a redirection. I'm using `Url.RouteUrl(..)` and during my unit tests this fails since the `Controller.Url` parameter is not pre-filled. I tried a lot of things, among others attempting to stub `UrlHelper` (which failed), manually creating a `UrlHelper` with a `RequestContext` that has a stubbed `HttpContextBase` (which failed on a `RouteCollection.GetUrlWithApplicationPath` call). I have searched Google but found virtually nothing on the subject. Am I doing something incredibly stupid using `Url.RouteUrl` in my Controller action? Is there an easier way? To make it even worse, I'd like to be able to test the returned URL in my unit test - in fact I'm only interested in knowing it's redirecting to the right route, but since I'm returning an URL instead of a route, I would like to control the URL that is resolved (eg. by using a stubbed `RouteCollection`) - but I'll be happy to get my test passing to begin with.

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