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: uri_test.rb
    path of file: ./repos/artichoke/artichoke-backend/src/extn/stdlib/uri
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'uri'

module URI
  class RS
    
def uri_decode_www_form
  ary = URI.decode_www_form('a=1&a=2&b=3')
  raise unless ary == [%w[a 1], %w[a 2], %w[b 3]]
  raise unless ary.assoc('a').last == '1'
  raise unless ary.assoc('b').last == '3'
  # this line fails on YARV
  # raise unless ary.rassoc('a').last == '2'
  raise unless ary.to_h == { 'a' => '2', 'b' => '3' }
end