Because you don’t know what you’ll need that wrapper beforehand, that’s my entire point.
Unless you’re only doing trivial changes, the chances are very high that you won’t be able to design the class structure. Or, you end up essentially writing the code to be able to write the tests, which kind of defeats the purpose.
That’s kind of the whole philosophy, though. The tests are the main way you understand what you’re doing, the working code is just an addition on top of that. Presumably, there’s a way to do that without repeating yourself - although I’m not turning up much on a quick look.
Because you don’t know what you’ll need that wrapper beforehand, that’s my entire point.
Unless you’re only doing trivial changes, the chances are very high that you won’t be able to design the class structure. Or, you end up essentially writing the code to be able to write the tests, which kind of defeats the purpose.
That’s kind of the whole philosophy, though. The tests are the main way you understand what you’re doing, the working code is just an addition on top of that. Presumably, there’s a way to do that without repeating yourself - although I’m not turning up much on a quick look.