In Ruby

first_excercise.rb

require 'minitest/autorun'
require 'minitest/pride'

# Will return a single code and code set if one exists in the code sets that are
# passed in. Returns a hash with a key of code and code_set if found, nil otherwise
def preferred_code(preferred_code_sets, codes_attribute=:codes, value_set_map=nil)
  codes_value = send(codes_attribute)
  preferred_code_sets = value_set_map ? (preferred_code_sets & value_set_map.collect{|cs| cs["set"]}) : preferred_code_sets
  matching_code_sets = preferred_code_sets & codes_value.keys
  #if matching_code_sets.present? <= present is only used in rails empty? is the ruby version of present?
  unless matching_code_sets.empty?
    if value_set_map
      matching_code_sets.each do |matching_code_set|
        matching_codes = codes_value[matching_code_set] & value_set_map.collect{|cs| cs["set"] == matching_code_set ? cs["values"] : []}.flatten.compact
        if !matching_codes.empty?
          return {'code' => matching_codes.first, 'code_set' => matching_code_set}
        end
      end
    else
      code_set = matching_code_sets.first
      {'code' => codes_value[code_set].first, 'code_set' => code_set}
    end
  else
    nil
  end
end

describe 'TestMethods' do
  describe 'preferred_code' do
    def codes;{}; end
    it "#returns nil" do
      preferred_code([]).must_be_nil
    end
    describe 'the else scenario' do
    def codes;{'code' => 0, 'code_set' => 0}; end
      it "value_set_map is nil" do
        preferred_code(['set','code', 'code_set','done']).must_equal({'code' => 1, 'code_set' => 1})
      end
    end
  end
end