We had a problem where running individual specs worked as expected, but running rake ran the whole test suite twice. (BTW, We are running Rails 3.0.1 and RSpec 2.0.1.) It looks like the problem is that we had run ‘rails generate rspec:install’ back when we were running RSpec 2.0.0.beta.22, and since, we upgraded to RSpec-2.0.1. It appears that the RSpec installer for the beta version created an rspec.rake file under lib/tasks, which is no longer required for RSpec 2.0.1, and is effectively duplicitous of what is invoked through the gem’s own rake tasks (it would seem).
I removed rspec.rake and now rake only runs the test suite once! Leave a comment if it this was helpful.