Example from https://github.com/turingschool/enums-exercises/blob/master/test/solutions/reduce_test.rb

reduce_it_real_good.rb

require 'minitest'
require 'minitest/autorun'

class ReduceTest < Minitest::Test
  def test_capitalize_keywords_in_phrase_one_fish_two_fish_red_fish_blue_fish
    keywords = ["fish", "blue"]
    phrase = 'one fish two fish red fish blue fish'

    result = phrase.split.reduce do |updatedPhrase, word|
      new_word = word

      if keywords.include?(word)
        new_word = word.upcase
      end

      updatedPhrase + " " + new_word # we want to keep a space between words
    end
    assert_equal 'one FISH two FISH red FISH BLUE FISH', result
  end
end