How can I unit test an MVC UserViewControl?

Question

I've been trying for a while now to write a unit test for a UserViewControl in ASP.NET MVC. I'd like to get to code that looks something like this:

[TestMethod]
public void HaveControlToDisplayThings()
{
    var listControl = new ControlUnderTest();
    var viewData = new ViewDataDictionary<IList<string>>(this.repo.GetMeSomeData());

    // Set up a ViewContext using Moq.
    listControl.SetFakeViewContext(viewData);
    listControl.ViewData = viewData;
    listControl.RenderView(listControl.ViewContext);

    // Never got this far, no idea if this will work :)
    string s = listControl.ViewContext.HttpContext.Response.Output.ToString();
    Assert.AreNotEqual(0, s.Length);
    foreach (var item in this.repo.GetMeSomeData())
    {
        Assert.IsTrue(s.IndexOf(item) != -1);
    }
}

Unfortunately, no matter what I try I get errors from deep inside RenderView. This is caused (as far as I can tell) by the static HttpContext.Current object being useless - I get NullReferenceExceptions from System.Web.UI.Page.SetIntrinsics.

I tried using Phil Haack's HttpSimulator which gave me a HttpContext object but I found I also needed to specify a fake HttpBrowserCapabilities object to get slightly further:

Subtext.TestLibrary.HttpSimulator simulator = new HttpSimulator();
simulator.SimulateRequest();
var browserMock = new Mock<HttpBrowserCapabilities>();
browserMock.Expect(b => b.PreferredRenderingMime).Returns("text/html");
browserMock.Expect(b => b.PreferredResponseEncoding).Returns("UTF-8");
browserMock.Expect(b => b.PreferredRequestEncoding).Returns("UTF-8");
HttpContext.Current.Request.Browser = browserMock.Object;

Now I get exceptions on property accesses on that object. I mocked as many as I could, but seemed to be getting nowhere fast.

Has anyone managed to make this work?

Answer 1

Unfortunately, the ASP.NET viewengine uses the VirtualPathProvider in the ASP.NET hosting environment. To make matters worse, I traced some of the other code using Reflector and found that there is other dependencies to some hardcode references to VirtualPath utilities. I hope they fix this in the release so we can truly test our Views and how they are rendered.