ASP.NET pages inside unit tests - AppDomainUnloadedException

LLook — Tue, 18 Nov 2008 17:56:09 GMT

Hello, I am experiencing a difficulty with running ASPX pages outside of IIS and even outside of HttpRuntime. These practices are not well documented, but I hope someone has already solved similar problem.

My goal is simple: Somehow create an instance of an ASPX page, run it and test what happens. Test values of some page's properties, properties of its controls and so on.

Here's where I came:

Create a new application domain (ApplicationHost.CreateApplicationHost).
Compile the page and get its type (ClientBuildManager).
Create a new HttpContext.
Construct the page (Type.GetConstructor...).
Then I can subscribe some events, if I want to test the page during its life-cycle.
Run the page (page.ProcessRequest). Documentation says that this method is "not intended to be used directly from your code". However I didn't find any other way...

And it works. This is the full code of a sample test fixture:

1    using System;
2    using System.Web;
3    using System.Web.Compilation;
4    using System.Web.Hosting;
5    using System.Web.UI;
6    using NUnit.Framework;
7    using NUnit.Framework.SyntaxHelpers;
8    
9    namespace PageSharp.Incubator.Tests.Learning
10   {
11       /// <summary>
12       /// Test how could pages be programatically instantiated and executed.
13       /// </summary>
14       [TestFixture]
15       public class PageLifeCycleLearningTest : MarshalByRefObject
16       {
17           private string _virtualDir = "/";
18           private string _appDir;
19           private PageLifeCycleLearningTest _host;
20   
21           public PageLifeCycleLearningTest()
22           {
23               _appDir = System.IO.Directory.GetCurrentDirectory().TrimEnd("bin".ToCharArray());
24           }
25   
26           [TestFixtureSetUp]
27           public void SetUp()
28           {
29               _host = (PageLifeCycleLearningTest)
30                   ApplicationHost.CreateApplicationHost(typeof(PageLifeCycleLearningTest), _virtualDir, _appDir);
31           }
32   
33           [Test]
34           public void TestSomeFact()
35           {
36               _host.TestSomeFact_Run();
37           }
38   
39           private void TestSomeFact_Run()
40           {
41               var page = CreatePage("~/default.aspx", String.Empty);
42               page.PreInit += new EventHandler(TestSomeFact_PreInit);
43               page.ProcessRequest(HttpContext.Current);
44   
45               var ctl = (System.Web.UI.WebControls.Label) page.FindControl("ctl00$ContentPlaceHolder1$WebUserControl11$Label1");
46               Assert.That(ctl.Text, Is.EqualTo("Hello World!"));
47           }
48   
49           private void TestSomeFact_PreInit(object sender, EventArgs e)
50           {
51               var page = (Page)sender;
52               var ctl = (System.Web.UI.WebControls.Label)page.FindControl("ctl00$ContentPlaceHolder1$WebUserControl11$Label1");
53               Assert.That(ctl, Is.Null);
54           }
55   
56           /// <summary>
57           /// Compile and instantiate a page.
58           /// </summary>
59           /// <param name="virtualPath">Virtual path.</param>
60           /// <param name="queryString">Query string.</param>
61           /// <returns>Instance of the page.</returns>
62           private Page CreatePage(string virtualPath, string queryString)
63           {
64               var cbm = new ClientBuildManager(_virtualDir, _appDir);
65               var type = cbm.GetCompiledType(virtualPath);
66               var writer = new System.IO.StringWriter();
67               HttpContext.Current = new HttpContext(new SimpleWorkerRequest(virtualPath, queryString, writer));
68               Page page = (Page)type.GetConstructor(new Type[] { }).Invoke(new object[] { });
69   
70               return page;
71           }
72       }
73   }
74

There's just one remaining problem: A few moments after the test runs and passes, something throws System.AppDomainUnloadedException exception, with no stack trace available:

I can't find a way to avoid it. Probably I have to clean the AppDomain somehow, but how?

Installation and Setup

ASP.NET pages inside unit tests - AppDomainUnloadedException