[jroesch]

I misread your comment, usually people challenge that point. I totally agree that it is difficult to talk about maintainability in an objective fashion, but there is something to be said about having as many of your assumptions in your codebase vs. your test suite. My experiences working in a Ruby code base is that many assumptions have been encoded in the tests, and not notated in the main code base. When those assumptions change there is a large burden on the programmer of having to unify ad-hoc assumptions from both the test cases and main code base. Validating whether those assumptions still hold, or if it is a test from 3 years ago, and has only been vacuously passing.

I found working in a big Ruby code base that this required spending a non trivial amount of time unifying the two. In that regard by minimizing the amount of test code one has to write and maintain I would argue that maintainability goes up. I've also seen a lot of FP practitioners boasting about relatively low test to code ratios, while in the Ruby world often times you have at least 2x test code, since often times you even have to validate assumptions like `object.responds_to? :foo`.