The type initializer for 'System.Web.Mvc.ViewEngines' threw an exception

Question

I am trying to unit test a void method that have controllercontext parameter and some more to send email. Email template render partial view using view engine. I mocked controllercontext. So render view throw an exception because ControllerContext have null value.

public static string RenderViewToString(ControllerContext context, string viewPath, object model, bool partial = false)
        {
            var viewEngineResult = partial ? ViewEngines.Engines.FindPartialView(context, viewPath) : ViewEngines.Engines.FindView(context, viewPath, null);

            if (viewEngineResult == null)
                throw new FileNotFoundException("View cannot be found.");

            var view = viewEngineResult.View;
            context.Controller.ViewData.Model = model;

            var result = String.Empty;

            using (var sw = new StringWriter())
            {
                var ctx = new ViewContext(context, view,
                                            context.Controller.ViewData,
                                            context.Controller.TempData,
                                            sw);
                view.Render(ctx, sw);
                result = sw.ToString();
            }

            return result;
        }

Answer 1

I dont think the error is with your code. I think it is with you test project does not have all the dependencies, in package mananger, with the test project set at the Default project intal

PM > Install-Package Microsoft.AspNet.WebPages

I forget to add this everytime I do test on a MVC project.

Answer 2

All you need is to install Microsoft.Asp.Net.WebPages in your test solution from the Nuget Package Manager and try to build your solution and then your unit tests will work properly.