This seems optimized for creation of small apps (and is also presented very well). But what striked me watching the intriduction video: When you revisit your a written app, it seems hard to understand whats going on and also hard to get a feel for if all functionality have been implemented and works. How does testing your app with this tool work? How does it help with maintaining a written app to lets say add a new functionality (when you have forgotten all about where your data is stored, where it is read from, what your queries where when you wrote them etc.).