Set Locale when using Auth::loginUsingId for phpunit

I have several languages in my Laravel 5.2 app. Each locale is stored in DB in th User Model. So, each time a user log, the locale must update.

Thing is in my Test, I use a lot Auth::loginUsingId, because I need to test function with differents user profiles.

So, I don't want to append to each of those calls with a App::setLocale(Auth::user->locale), nor extract it to a function.

Any Idea how should I do it???