Question

I would like to unit test the Initialize method of a Controller object. The Initialize () method basically extracts the player’s ID from the cookies collection of the request object and retrieves the current player object from the database. Then the player object is stored in the controller object’s CurrentPlayer property. I have the following code for the unit test. This test is basically written for the Index () method of the controller:

[Test]
public void Index_ReturnsJsonResult ()
{
   var _gameRepositoryMock = GameRepositoryCreator.Create (5);

   var _formsAuthenticationMock = new Mock<IFormsAuthentication> ();

   var _chooseOpponentController = new ChooseOpponentController (_gameRepositoryMock.Object, _formsAuthenticationMock.Object);


    var cookie = new HttpCookie (cookieName);
    cookie.Value = player.PlayerID + "_encrypted";

    var cookies = new HttpCookieCollection ();
    cookies.Add (cookie);

    var httpRequestMock = new Mock<HttpRequestBase> ();
    httpRequestMock.Setup (x => x.Cookies).Returns (cookies);
    httpRequestMock.Setup (x => x.IsAuthenticated).Returns (true);

    var httpContextMock = new Mock<HttpContextBase> ();
    httpContextMock.Setup (x => x.Request).Returns (httpRequestMock.Object);

    var rd = new RouteData ();
    rd.Values.Add ("action", "Index");
    rd.Values.Add ("controller", "ChooseOpponent");

    var requestContext = new RequestContext (httpContextMock.Object, rd); 

    _formsAuthenticationMock.Setup (x => x.Decrypt (cookie.Value)).Returns (player.PlayerID + "");   

    (_chooseOpponentController as IController).Execute (requestContext);

    Assert.IsNotNull (_chooseOpponentController.CurrentPlayer);

    ... // test other things for the Index () method
}

The Index () method is declared as:

 [Authorize, SavePlayerStatus(Order=2), CommitChanges(Order=1)]
 public ActionResult Index ()
 { ... }

The Initialize () method is executed successfully but after that I get an exception with the following message: “Object reference not set to an instance of an object.”, and the stack trace looks like this:

at System.Web.Compilation.BuildManager.GetCacheKeyFromVirtualPath(VirtualPath virtualPath, Boolean& keyFromVPP)
at System.Web.Compilation.BuildManager.GetVPathBuildResultFromCacheInternal(VirtualPath virtualPath, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
at System.Web.Mvc.BuildManagerWrapper.System.Web.Mvc.IBuildManager.FileExists(String virtualPath)
at System.Web.Mvc.BuildManagerViewEngine.FileExists(ControllerContext controllerContext, String virtualPath)
at System.Web.Mvc.VirtualPathProviderViewEngine.GetPathFromGeneralName(ControllerContext controllerContext, List`1 locations, String name, String controllerName, String areaName, String cacheKey, String[]& searchedLocations)
at System.Web.Mvc.VirtualPathProviderViewEngine.GetPath(ControllerContext controllerContext, String[] locations, String[] areaLocations, String locationsPropertyName, String name, String controllerName, String cacheKeyPrefix, Boolean useCache, String[]& searchedLocations)
at System.Web.Mvc.VirtualPathProviderViewEngine.FindView(ControllerContext controllerContext, String viewName, String masterName, Boolean useCache)
at System.Web.Mvc.ViewEngineCollection.<>c__DisplayClassc.<FindView>b__b(IViewEngine e)
at System.Web.Mvc.ViewEngineCollection.Find(Func`2 lookup, Boolean trackSearchedPaths)
at System.Web.Mvc.ViewEngineCollection.FindView(ControllerContext controllerContext, String viewName, String masterName)
at System.Web.Mvc.ViewResult.FindView(ControllerContext context)
at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<>c__DisplayClass1e.<InvokeActionResultWithFilters>b__1b()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)
at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)

Any help is appreciated.

Answer 1

By calling Execute you are essentially calling the entire MVC pipeline. This includes the view lookup logic that tries to go to disk and find your view files. The part that’s failing is the ASP.NET compilation system that is not initialized properly.

For a unit test, you are executing too much. I would write 2 tests: one that verifies that the Index method does the right thing, and one that verifies that the Initialize method does the right thing. Everything else (the fact that Initialize gets called before the action method, etc) is MVC plumbing that you should not need to worry about.