Unit Testing ASP.NET MVC Controller Action contains specific ActionFilter Attributes

ActionFilters in ASP.NET MVC are great.

You can now easily share logic between controllers without having to inherit from a base controller, that does the common work.

I have a content heavy application that supports a set of layouts. Each layout is rendered by setting the Layout view dynamically, which I do from an ActionFilter. My ActionFilter is fully tested, but when you delegate work to an ActionFilter, you should write a test that ensures the filter is defined on the action.

Not surprisingly, this is very simple and relies on reflection (Download from Gist: https://gist.github.com/2605628):


/// Verifies the controller action, contains an attribute of the specified attributeType. /// /// The controller. /// The action method. /// Type of the attribute to look for. /// Returns true if the attribute was present on the action. Otherwise false. public static bool VerifyControllerActionAttribute(this Controller controller, Func action, Type attributeType) { MethodInfo methodInfo = action.Method; object[] attributes = methodInfo.GetCustomAttributes(attributeType, true); return attributes.Any(a => a.GetType() == attributeType); }

And the usage looks like this:

[TestMethod] public void Index_ContainsTemplateLayoutAttribute() { HomeController controller = new HomeController(); bool containsAttribute = controller.VerifyControllerActionAttribute(controller.Index, typeof(TemplateLayoutAttribute)); Assert.IsTrue(containsAttribute); }

Need an introduction? Watch a video about unit testing ASP.NET and MVC based web apps on Vimeo, published by Typemock.

Martin H. Normark

Product and UX Hacker. Web and iOS developer.