Is it best practice to test my Web API controllers directly or through an HTTP client?

Question

I\'m adding some unit tests for my ASP.NET Core Web API, and I\'m wondering whether to unit test the controllers directly or through an HTTP client. Directly would look roughly

Answer 1

I never have liked mocking in that as applications mature the effort spent on mocking can make for a ton of effort.

I like exercising endpoints by direct Http calls. Today there are fantastic tools like Cypress which allow the client requests to be intercepted and altered. The power of this feature along with easy Browser based GUI interaction blurs traditional test definitions because one test in Cypress can be all of these types Unit, Functional, Integration and E2E.

If an endpoint is bullet proof then error injection becomes impossible from outside. But even errors from within are easy to simulate. Run the same Cypress tests with Db down. Or inject intermittent network issue simulation from Cypress. This is mocking issues externally which is closer to a prod environment.