I've written versions of an RSpec helper several times for modifying ENV in specs. Here's one:
https://gist.github.com/soulcutter/b54e6e83c0a9a0dca1ff1ff9ffde2a4e
I shy away from the climate_control gem because a whole 'nother dependency for this seems meh - but go ahead and poke holes in my opinion/implementation


