How can you unit test an Action Filter in ASP.NET Web Api?

Question

I was looking to add an Action Filter to my service to handle adding link data to the response message. I have found that I need to mock HttpActionExecutedContext but it's a difficult class to mock, how are you dealing with Action Filter testing?

Answer 1

You can create a fake for HttpActionExecutedContext as below:

public static HttpActionContext CreateActionContext(HttpControllerContext controllerContext = null, HttpActionDescriptor actionDescriptor = null) {     HttpControllerContext context = controllerContext ?? ContextUtil.CreateControllerContext();     HttpActionDescriptor descriptor = actionDescriptor ?? new Mock<HttpActionDescriptor>() { CallBase = true }.Object;     return new HttpActionContext(context, descriptor); }  public static HttpActionExecutedContext GetActionExecutedContext(HttpRequestMessage request, HttpResponseMessage response) {     HttpActionContext actionContext = CreateActionContext();     actionContext.ControllerContext.Request = request;     HttpActionExecutedContext actionExecutedContext = new HttpActionExecutedContext(actionContext, null) { Response = response };     return actionExecutedContext; } 

I just copied and pasted that code from the ASP.NET Web API source code: ContextUtil class. Here is a few examples on how they tested some built in filters:

• AuthorizeAttributeTest

• ActionFilterAttributeTest

ActionFilterAttributeTest is the test class for ActionFilterAttribute which is an abstract class but you will get the idea.

Answer 2

Just new one up.

private HttpActionContext CreateExecutingContext() {     return new HttpActionContext { ControllerContext = new HttpControllerContext {   Request = new HttpRequestMessage() } }; }  private HttpActionExecutedContext CreateExecutedContextWithStatusCode(HttpStatusCode statusCode) {     return new HttpActionExecutedContext     {         ActionContext = new HttpActionContext         {             ControllerContext = new HttpControllerContext             {                 Request = new HttpRequestMessage()             }         },         Response = new HttpResponseMessage         {             StatusCode = statusCode,             Content = new StringContent("blah")         }     }; }