I'm not sure not if software development questions should be solved with a reference to "Ruby's culture". Wouldn't "what works best" be a better criteria?

I've done more Ruby than Python altogether. It's true that I am no longer doing Ruby - mostly because it is too slow for anything beyond a fairly simple web platform (I would welcome an improvement in Ruby performance).

I would argue that the time spent on the tests could instead be spent on an actual spec.