B team

bottles_b.rb

class Bottles

  def song
    verses(99, 0)
  end

  def verses(upper_bound, lower_bound)
    upper_bound.downto(lower_bound).map { |i| verse(i) }.join("\n")
  end

  def verse(verse_number)
    current_bn = create_bottles(verse_number)
    next_bn    = create_bottles(current_bn.next)

    "#{current_bn.quantity.capitalize} #{current_bn.container} of beer on the wall, " +
    "#{current_bn.quantity} #{current_bn.container} of beer.\n" +
    "#{current_bn.action}, " +
    "#{next_bn.quantity} #{next_bn.container} of beer on the wall.\n"
  end
  
  private
  def create_bottles(number) 
  	if number == 0
  		BottleNumber0.new(number)
  	elsif number == 1
  		BottleNumber1.new(number)
  	elsif number == 6
  		BottleNumber6.new(number)
  	else
  		BottleNumber.new(number)
  	end
  end
end

class BottleNumber
  attr_reader :number

  def initialize(number)
    @number = number
  end

  def container  
    'bottles'
  end

  def pronoun
      'one'
  end

  def quantity
      number.to_s
  end

  def action
      "Take #{pronoun} down and pass it around"
  end

  def next
      number - 1
  end

end

class BottleNumber0 < BottleNumber
  def quantity
    'no more'    	
  end
  
  def action
   	 "Go to the store and buy some more"
  end
  
  def next
      99
  end

end

class BottleNumber1 < BottleNumber
  def pronoun
	'it'
  end
  
  def container
    'bottle'
  end
end

class BottleNumber6 < BottleNumber
  def quantity
  	"1"
  end
  
  def container  
    'six-pack'
  end
end

bottles_b_test.rb

gem 'minitest', '~> 5.3'
require 'minitest/autorun'
require 'minitest/pride'
require_relative '../lib/bottles'


class BottlesTest < Minitest::Test

  attr_reader :bottles
  def setup
    @bottles = ::Bottles.new
  end

  def test_the_first_verse
    expected = <<-VERSE
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.
VERSE
    assert_equal expected, bottles.verse(99)
  end

  def test_another_verse
    expected = <<-VERSE
89 bottles of beer on the wall, 89 bottles of beer.
Take one down and pass it around, 88 bottles of beer on the wall.
VERSE
    assert_equal expected, bottles.verse(89)
  end

  def test_verse_2
    expected = <<-VERSE
2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.
    VERSE
    assert_equal expected, bottles.verse(2)
  end

  def test_verse_1
    expected = <<-VERSE
1 bottle of beer on the wall, 1 bottle of beer.
Take it down and pass it around, no more bottles of beer on the wall.
    VERSE
    assert_equal expected, bottles.verse(1)
  end

  def test_verse_0
    expected = <<-VERSE
No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
    VERSE
    assert_equal expected, bottles.verse(0)
  end

  def test_a_couple_verses
    expected = <<-VERSES
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.
VERSES
    assert_equal expected, bottles.verses(99, 98)
  end

  def test_a_few_verses
    expected = <<-VERSES
2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take it down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.
VERSES
    assert_equal expected, bottles.verses(2, 0)
  end

  def test_the_whole_song
    assert_equal bottles.verses(99, 0), bottles.song
  end
  
  def test_7
  	expected = <<-VERSE
7 bottles of beer on the wall, 7 bottles of beer.
Take one down and pass it around, 1 six-pack of beer on the wall.
VERSE
    assert_equal expected, bottles.verse(7)
  end
  
  def test_6
    expected = <<-VERSE
1 six-pack of beer on the wall, 1 six-pack of beer.
Take one down and pass it around, 5 bottles of beer on the wall.
VERSE
    assert_equal expected, bottles.verse(6)   
  end
  
end