spec.rb

scenario "have ability to edit profile", :js => true do
  @ability.should be_able_to(:edit, @profile)
end

spec_helper.rb

RSpec.configure do |config|
  config.include Capybara

  config.before(:each) do
    Capybara.current_driver = :akephalos if example.metadata[:js]
    Capybara.current_driver = example.metadata[:driver] if example.metadata[:driver]
  end

  config.after(:each) do
    Capybara.use_default_driver if example.metadata[:js]
    Capybara.use_default_driver if example.metadata[:driver]
  end
end

Has better support than the original Gist for both specifying the use of JS using default Akephalos driver, or allowing the driver to be specified explicitly