+1 Striving to make your code testable is almost always worth it. Someone might ask this guy to add some error handling to his code for example. :) Then he wil

+1 Striving to make your code testable is almost always worth it. Someone might ask this guy to add some error handling to his code for example. :) Then he will find out that by writing code, however simple, that a "works on my machine" I.e. is proven to work in a single happy path context is painful to change. Writing code that runs in multiple contexts (composed as an app or decomposed for testing) is intrinsically more easy to work with and change.