How do I add conditional rubygem requirements to a gem specification?

Question

Is it possible to add a gem dependency only if the person is using a certain version of ruby?

Background: I\'m working on a fork of a project that u

Answer 1

Gemspecs are just ruby files anyway, so you can execute any ruby code inside them, so:

spec.add_dependency = 'test-unit', '>= 2.0' if RUBY_VERSION =~ '1.9' 

EDIT: Specs run only on the builders machine.