title: Widgets in single file vs multiple files in Flutter
body: <p>I am wondering what is the best practice according to organization of widgets in Flutter. Let's image I am writing some bigger widget like side bar in the application. This widget consists of several smaller widgets (like title, some greeting, user data, list of menu buttons, etc.) that I know won't be reused in other widgets. And now my question is - should all of them be kept in the same file (widgets or methods that build these widgets) as their context is the same or maybe should I separate them into large amount of small files in order to write tests for them more easily?</p>