http://steve-yegge.blogspot.com/2008/02/portrait-of-n00b.htm... This point reminds me of "Portait of a Noob". For people who understand what the codebase is doing, it's more effective to have as much code on screen as possible. For "noobs", since you don't know what the code does, less code on screen is better. Additionally, these 'noobs' like more meta-program stuff like type declarations (or unit tests) which don't actually contribute to the program itself, but provide a safety barrier to prevent things from going wrong. (Whereas, if you know what the code is doing and it goes wrong, you can just fix it).

It's fair to say "a program not covered by unit tests can still be good enough to get the job done" (& to suggest that this is under-appreciated), but not having sufficient test coverage significantly raises the barrier to entry for those not familiar with the code ("noobs") from contributing.

(EDIT: I wrote my comment before parent's edit)