Translate Phrases to Pig Latin

pig_latin_spec.rb

require 'spec_helper'

module PigLatin
  extend self

  def translate(phrase)
    words = phrase.scan(/\w+/)
    translations = words.map { |word| [word, Translate[word]] }
    translations.inject(phrase) do |template, (original, translated)|
      template.gsub(original, translated)
    end
  end

  Translate = -> word {
    case word
    when /^[aeiou]/
      word + 'ay'
    when /^[A-Z]/
      Translate[word.downcase].capitalize
    else
      word[1..-1] + word[0] + 'ay'
    end
  }
end

describe  "Pig latin" do
  subject { PigLatin.translate(phrase) }

  describe 'hello' do
    let(:phrase) { 'hello' }
    it { should == 'ellohay' }
  end

  describe 'apples' do
    let(:phrase) { 'apples' }
    it { should == 'applesay' }
  end

  describe 'eat world' do
    let(:phrase) { 'eat world' }
    it { should == 'eatay orldway' }
  end

  describe 'Hello' do
    let(:phrase) { 'Hello' }
    it { should == 'Ellohay' }
  end

  describe 'Eat' do
    let(:phrase) { 'Eat' }
    it { should == 'Eatay' }
  end

  describe 'hello...  world?!' do
    let(:phrase) { 'hello...  world?!' }
    it { should == 'ellohay...  orldway?!' }
  end
end