ASP.NET MVC: Unit testing controllers that use UrlHelper

Question

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

Hope this helps:

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);

A modified implementation from eu-ge-ne. This one returns a generated link based on the routes defined in the application. eu-ge-ne's example always returned a fixed response. The approach below will allow you to test that the correct action/controller and route information is being passed into the UrlHelper - which is what you want if you are testing call to the UrlHelper.

var context = new Mock<HttpContextBase>();
var request = new Mock<HttpRequestBase>();
var response = new Mock<HttpResponseBase>();
var session = new Mock<HttpSessionStateBase>();
var server = new Mock<HttpServerUtilityBase>();

context.Setup(ctx => ctx.Request).Returns(request.Object);
context.Setup(ctx => ctx.Response).Returns(response.Object);
context.Setup(ctx => ctx.Session).Returns(session.Object);
context.Setup(ctx => ctx.Server).Returns(server.Object);

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 NameValueCollection());

response.Setup(x => x.ApplyAppPathModifier(It.IsAny<string>())).Returns<string>(x => x);

context.SetupGet(x => x.Request).Returns(request.Object);
context.SetupGet(x => x.Response).Returns(response.Object);

var routes = new RouteCollection();
MvcApplication.RegisterRoutes(routes);
var helper = new UrlHelper(new RequestContext(context.Object, new RouteData()), routes);

This post may be useful if you want to mock HttpContextBase class.

http://www.hanselman.com/blog/ASPNETMVCSessionAtMix08TDDAndMvcMockHelpers.aspx

Building off the answer by @eu-ge-ne which helped me a great deal:

I had an ActionResult that did a redirect as well as had an UpdateModel call with a FormCollection parameter. For the UpdateModel() to work I had to add this to my Mocked HttpRequestBase:

FormCollection collection = new FormCollection();
collection["KeyName"] = "KeyValue";

request.Setup(x => x.Form).Returns(collection);
request.Setup(x => x.QueryString).Returns(new NameValueCollection());

To test that the redirected URL was correct, you can do the following:

RedirectResult result = controller.ActionName(modelToSubmit, collection) as RedirectResult;
Assert.AreEqual("/Expected/URL", result.Url);

http://kbochevski.blogspot.com/2010/06/unit-testing-mvcnet.html discusses how to cover all the layers with unit tests.It uses Rhino and MVC.Contrib for the controllers testing. The source code on google may be of a great help.