c# - Mocking a controller to test ViewEngine inside an Area - nullreference and RouteData -

i have area in mvc site. area has typical controller/model/view setup.

as controller have following code:

public class documentcreatorcontroller : controller {     // get: templates/documentcreator     public actionresult offertemplate(basedocumentviewmodel data)     {         return this.pdf(nameof(offertemplate), data, "file.pdf");     } } 

the method this.pdf couple of stuff, interesting comes down viewengine call:

var viewresult = viewengines.engines.findpartialview(controllercontext, partialviewname); 

here call findpartialview controllercontext , partialviewname. partialviewname comes nameof(offertemplate) controller action offertemplate. think controllercontext challenge.

my challenge:

when want set in unit test (using moq), have following code based on pages such mocking routedata class in system.web.routing mvc applications , mocking asp.net-mvc controller context:

[testmethod] public void offertemplate() {     var ctr = setupcontrollerwithcontext();  }  private static documentcreatorcontroller setupcontrollerwithcontext() {     var routedata = new routedata();     routedata.values.add("controller", "documentcreatorcontroller");     routedata.values.add("action", "offertemplate");       var request = new mock<httprequestbase>();     request.expect(r => r.httpmethod).returns("get");     var mockhttpcontext = new mock<httpcontextbase>();     mockhttpcontext.expect(c => c.request).returns(request.object);     var controllercontext = new controllercontext(mockhttpcontext.object         , routedata, new mock<controllerbase>().object);      documentcreatorcontroller ctr = new documentcreatorcontroller();     ctr.controllercontext = controllercontext;     return ctr; } 

which gives following error:

eesy.websites.api.tests.controllers.documentcreatorcontrollertest.offertemplate threw exception: system.nullreferenceexception: object reference not set instance of object.

this don't understand.

my folder setup:

debug image on controllercontext on calling findpartialview:

anyone have idea? because setup routedata wrong?

you trying mock , test framework code. abstract functionality out code control can test in isolation if needed.

currently action , extension controller tightly coupled external 3rd party dependencies. if goal test controller action flow in isolation advised abstract out 3rd party pdf generation can mocked easier testability.

public interface idocumentservice {     actionresult topdf(controller arg1, string arg2, object arg3, string arg4); } 

the controller explicitly depend on abstraction via constructor injection.

public class documentcreatorcontroller : controller {     private readonly idocumentservice render;      documentcreatorcontroller(idocumentservice render) {         this.render = render;     }      // get: templates/documentcreator     public actionresult offertemplate(basedocumentviewmodel data) {         return render.topdf(this, nameof(offertemplate), data, "file.pdf");     } } 

so test controller's pdf generation process need mock abstraction.

[testmethod] public void offertemplate() {     //arrange         var servicemock = new mock<idocumentservice>();     //...setup mock use case      var controller = new documentcreatorcontroller(servicemock.object);     var data = new basedocumentviewmodel {         //...     };      //act     var actual = controller.offertemplate(data);      //assert     //...assert behavior } 

the actual implementation of service encapsulate actual functionality , registered dependency injection container along abstraction.

to test actual generation need integration test topic.