fake_chargify is a helper for faking web requests and responses to and from the Chargify API. You can test Chargify within your application on a plane now. I am sure that happens all the time.
gem 'fake_chargify'
require 'fake_chargify'
Example, in spec_helper.rb
FakeChargify.activate!
RSpec.configure do |c|
c.before do
FakeChargify.clear!
end
end