Set request headers in Capybara+RackTest

set_request_headers.rb

# Patch to support customized request headers in your Capybara tests
# when you're using the RackTest driver, based on an Aslak Hellesøy's gist: 
# https://gist.github.com/358664
#
# Please note that some drivers don't allow access to headers, see:
# https://github.com/jnicklas/capybara/issuesearch?state=closed&q=header#issue/17

class Capybara::Driver::RackTest < Capybara::Driver::Base
  
  def env
    @env
  end
  
  def set_headers(headers)
    @env = env.nil? ? headers : env.merge(headers)
  end
  
end

class Capybara::Session
    
  def set_headers(headers)
    if driver.respond_to?(:set_headers)
      driver.set_headers headers
    else
      raise Capybara::NotSupportedByDriverError
    end
  end
  
end

# Steak sample test:
scenario "..." do
  page.set_headers({"HTTP_ACCEPT_LANGUAGE" => "es" })
end

it should be Capybara::RackTest::Driver