Creating a custom Capybara driver.

helper.rb

# spec/acceptance/support/helper.rb

# ... Other config stuff

Capybara.register_driver :mobile do |app|
  Capybara::RackTest::Driver.new(app, :headers => {'HTTP_USER_AGENT' => 'Mobile'})
end

def switch_driver(driver)  
  before(:each) do         
    Capybara.current_driver = driver
  end
 
  after(:each) do          
    Capybara.use_default_driver
  end
end