follow_redirect

# File actionpack/lib/action_controller/test_process.rb, line 377
    def follow_redirect
      if @response.redirected_to[:controller]
        raise "Can't follow redirects outside of current controller (#{@response.redirected_to[:controller]})"
      end

      get(@response.redirected_to.delete(:action), @response.redirected_to.stringify_keys)
    end