You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spec_files.rb
    path of file: ./repos/rack/test
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require_relative 'helper'

separate_testing do
  require_relative '../lib/ra
    
      def filesize(_); 10000 end
    end.new(DOCROOT)

    res = Rack::MockResponse.new(*files.call(env))

    res.status.must_equal 206
    res["content-length"].must_equal "209"
    res["content-range"].must_equal "bytes 0-3300/10000"
  end