Recently I’ve been working a lot with the new ASP.NET MVC framework, with Preview 1 (bleh) and the interim drop, Pre-Preview 3?
The ActionResult is a fantastic addition, making the framework far easier to test. However, I noticed I was basically doing the same thing for each test:

1. [Test]
2. public void TestSomething()
3. {
4.    var actionResult = controllerUT.Something() as RenderViewResult;
5.  
6.    If ( actionResult == null )
7.       Assert.Fail(“ActionResult was null.”);
8.  
9.    Assert.That(actionResult.ViewName, Is.EqualTo(“ViewName”));
10.    Assert.That(actionResult.ViewData, Is.Typeof(typeof(SomeClass)));
11.    Assert.That(((SomeClass)actionResult.ViewData).SomeProperty, Is.EqualTo(123));
12. }

Basically asserting the view name, view data type and maybe asserting a property or two on the view data. In the spirit of treating the test code as a first class citizen I decided to refactor out the duplication. The resulting refactoring turned the above into the following:

1. [Test]
2. public void TestSomething()
3. {
4.    controller.Something().AssertViewName(“ViewName”).AssertViewDataType<SomeClass>(c => Assert.That(c.SomeProperty, Is.EqualTo(123));
5. }

Which I personally think is alot nicer! Although I'm a little biased, so I thought I would share it and see what other people thought of it. Below is the code I came up with. Any and all suggestions (good or bad) are appreciated

1. namespace e4umsMN.Spec.Utils
2. {
3.     using System;
4.     using System.Web.Mvc;
5.     using NUnit.Framework;
6.     using NUnit.Framework.SyntaxHelpers;
7.  
8.     internal static class ActionResultHelper
9.     {
10.  
11.         #region Public statics (6)
12.  
13.         public static ActionResult AssertActionRedirect(this ActionResult actionResult, string actionName)
14.         {
15.             return actionResult.AssertNotNull<ActionRedirectResult>(arr => Assert.That(arr.Values["action"], Is.EqualTo(actionName)));
16.         }
17.  
18.         public static ActionResult AssertHttpRedirect(this ActionResult actionResult, string redirect)
19.         {
20.             return actionResult.AssertNotNull<HttpRedirectResult>(hrr => Assert.That(hrr.Url, Is.EqualTo(redirect)));
21.         }
22.  
23.         public static ActionResult AssertRenderViewResult(this ActionResult actonResult, Action<RenderViewResult> extraAssert)
24.         {
25.             return actonResult.AssertNotNull(extraAssert);
26.         }
27.  
28.         public static ActionResult AssertViewDataType<T>(this ActionResult actionResult, Action<T> viewDataAssert)
29.         {
30.             return actionResult.AssertRenderViewResult(a => viewDataAssert((T)a.ViewData));
31.         }
32.  
33.         public static ActionResult AssertViewDataType<T>(this ActionResult actionResult)
34.         {
35.             return actionResult.AssertRenderViewResult(a => Assert.That(a.ViewData, Is.TypeOf(typeof(T))));
36.         }
37.  
38.         public static ActionResult AssertViewName(this ActionResult actionResult, string viewName)
39.         {
40.             return actionResult.AssertRenderViewResult(a => Assert.That(a.ViewName, Is.EqualTo(viewName)));
41.         }
42.  
43.         #endregion Public statics
44.  
45.         #region Other statics (1)
46.  
47.         private static T AssertNotNull<T>(this object actionResult, Action<T> extraAssert)
48.         {
49.             if (actionResult == null)
50.                 Assert.Fail("ActionResult was null");
51.  
52.             extraAssert((T) actionResult);
53.  
54.             return (T) actionResult;
55.         }
56.  
57.         #endregion Other statics
58.  
59.     }
60. }

Posted on Thursday, May 15, 2008 6:59 PM development , tdd , aspnetmvc | Back to top