'ThingDoer' is a naming convention from Go (I'm not a fan of the fact that we have to live with the Delphi-ism that is IMyThing but at least it's just one lette

'ThingDoer' is a naming convention from Go (I'm not a fan of the fact that we have to live with the Delphi-ism that is IMyThing but at least it's just one letter). There is no requirement to define new interfaces except for a specific coding style in a team. It is best for most components to stay as plain and simple as possible, and for the module and component level testing to be applied with as little mocking as possible (because, most of the time, it is an anti-pattern imposed on us by what is sometimes named "London's school of testing" which is just bad practice and whoever perpetuates it should apologize).