Some time ago I was converting MVC ViewResult into html to use in some mocked integration tests and this is the nice error I got. Wonderful. Anyway, just wanted to post the screenshot because I think it is better to substitute part of the environment instead of trying to mock all this stuff. I strongly believe in end-to-end testing with tools like Selenium. Not that there is anything wrong with using mocks when testing 3rd party vendor api...
![Most useful error ever Screenshot of runtime error](/Data/Sites/1/images/articles/viewresult-most-usefull-error-ever.jpg)