My rake tasks for running Cucumber and RSpec tests are always using my development
environment.
Here are the relevant config files:
RAILS_ROOT
When you upgraded to Rails 3, did you perhaps do a global find and replace on RAILS_ENV?
Is the first line of test_helper.rb something other than this?
ENV["RAILS_ENV"] = "test"
In the actual environment variables, it should still be RAILS_ENV, not ::Rails.env, so make sure you don't have ENV["Rails.env"] = "test" for that line of code.
Make sure it looks like it used to. Not that I would know from having made this mistake personally... :-)