assign_parameters

# File actionpack/lib/action_controller/test_case.rb, line 145
    def assign_parameters(routes, controller_path, action, parameters = {})
      parameters = parameters.symbolize_keys.merge(:controller => controller_path, :action => action)
      extra_keys = routes.extra_keys(parameters)
      non_path_parameters = get? ? query_parameters : request_parameters
      parameters.each do |key, value|
        if value.is_a? Fixnum
          value = value.to_s
        elsif value.is_a? Array
          value = Result.new(value.map { |v| v.is_a?(String) ? v.dup : v })
        elsif value.is_a? String
          value = value.dup
        end

        if extra_keys.include?(key.to_sym)
          non_path_parameters[key] = value
        else
          path_parameters[key.to_s] = value
        end
      end

      # Clear the combined params hash in case it was already referenced.
      @env.delete("action_dispatch.request.parameters")

      params = self.request_parameters.dup
      %(controller action only_path).each do |k|
        params.delete(k)
        params.delete(k.to_sym)
      end
      data = params.to_query

      @env['CONTENT_LENGTH'] = data.length.to_s
      @env['rack.input'] = StringIO.new(data)
    end