When I run a test, I receive a type initializer exception without any descriptive message

MyTested.AspNetCore.Mvc uses a static constructor to bootstrap and prepare the test application. If your configuration is not valid, System.TypeInitializerException may be thrown. Depending on your test runner, you may not see a descriptive and helpful message.

In order to see more details about the problem, run the test in Debug mode and analyse the message of the InnerException.