"MVC" is not an idiomatic pattern in Go.
What's different is that the "model" is often e.g. a bare sql.DB and not an object repository, and the "view" is a template called directly by the controller, but "MVC" - even this kind, which isn't the original kind - doesn't have to be an auto-wired DI interface-laden mess. PHP and Java just made it that way.
Do you not do this? What do you do instead? I guess I can see how testing would be less painful with fewer layers, but at the cost of the production code becoming more entangled.