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w1zeman1p's solution

to Beer Song in the Ruby Track

Published at Feb 06 2019 · 0 comments
Instructions
Test suite
Solution

Note:

This exercise has changed since this solution was written.

Recite the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.

Note that not all verses are identical.

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.

97 bottles of beer on the wall, 97 bottles of beer.
Take one down and pass it around, 96 bottles of beer on the wall.

96 bottles of beer on the wall, 96 bottles of beer.
Take one down and pass it around, 95 bottles of beer on the wall.

95 bottles of beer on the wall, 95 bottles of beer.
Take one down and pass it around, 94 bottles of beer on the wall.

94 bottles of beer on the wall, 94 bottles of beer.
Take one down and pass it around, 93 bottles of beer on the wall.

93 bottles of beer on the wall, 93 bottles of beer.
Take one down and pass it around, 92 bottles of beer on the wall.

92 bottles of beer on the wall, 92 bottles of beer.
Take one down and pass it around, 91 bottles of beer on the wall.

91 bottles of beer on the wall, 91 bottles of beer.
Take one down and pass it around, 90 bottles of beer on the wall.

90 bottles of beer on the wall, 90 bottles of beer.
Take one down and pass it around, 89 bottles of beer on the wall.

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.

88 bottles of beer on the wall, 88 bottles of beer.
Take one down and pass it around, 87 bottles of beer on the wall.

87 bottles of beer on the wall, 87 bottles of beer.
Take one down and pass it around, 86 bottles of beer on the wall.

86 bottles of beer on the wall, 86 bottles of beer.
Take one down and pass it around, 85 bottles of beer on the wall.

85 bottles of beer on the wall, 85 bottles of beer.
Take one down and pass it around, 84 bottles of beer on the wall.

84 bottles of beer on the wall, 84 bottles of beer.
Take one down and pass it around, 83 bottles of beer on the wall.

83 bottles of beer on the wall, 83 bottles of beer.
Take one down and pass it around, 82 bottles of beer on the wall.

82 bottles of beer on the wall, 82 bottles of beer.
Take one down and pass it around, 81 bottles of beer on the wall.

81 bottles of beer on the wall, 81 bottles of beer.
Take one down and pass it around, 80 bottles of beer on the wall.

80 bottles of beer on the wall, 80 bottles of beer.
Take one down and pass it around, 79 bottles of beer on the wall.

79 bottles of beer on the wall, 79 bottles of beer.
Take one down and pass it around, 78 bottles of beer on the wall.

78 bottles of beer on the wall, 78 bottles of beer.
Take one down and pass it around, 77 bottles of beer on the wall.

77 bottles of beer on the wall, 77 bottles of beer.
Take one down and pass it around, 76 bottles of beer on the wall.

76 bottles of beer on the wall, 76 bottles of beer.
Take one down and pass it around, 75 bottles of beer on the wall.

75 bottles of beer on the wall, 75 bottles of beer.
Take one down and pass it around, 74 bottles of beer on the wall.

74 bottles of beer on the wall, 74 bottles of beer.
Take one down and pass it around, 73 bottles of beer on the wall.

73 bottles of beer on the wall, 73 bottles of beer.
Take one down and pass it around, 72 bottles of beer on the wall.

72 bottles of beer on the wall, 72 bottles of beer.
Take one down and pass it around, 71 bottles of beer on the wall.

71 bottles of beer on the wall, 71 bottles of beer.
Take one down and pass it around, 70 bottles of beer on the wall.

70 bottles of beer on the wall, 70 bottles of beer.
Take one down and pass it around, 69 bottles of beer on the wall.

69 bottles of beer on the wall, 69 bottles of beer.
Take one down and pass it around, 68 bottles of beer on the wall.

68 bottles of beer on the wall, 68 bottles of beer.
Take one down and pass it around, 67 bottles of beer on the wall.

67 bottles of beer on the wall, 67 bottles of beer.
Take one down and pass it around, 66 bottles of beer on the wall.

66 bottles of beer on the wall, 66 bottles of beer.
Take one down and pass it around, 65 bottles of beer on the wall.

65 bottles of beer on the wall, 65 bottles of beer.
Take one down and pass it around, 64 bottles of beer on the wall.

64 bottles of beer on the wall, 64 bottles of beer.
Take one down and pass it around, 63 bottles of beer on the wall.

63 bottles of beer on the wall, 63 bottles of beer.
Take one down and pass it around, 62 bottles of beer on the wall.

62 bottles of beer on the wall, 62 bottles of beer.
Take one down and pass it around, 61 bottles of beer on the wall.

61 bottles of beer on the wall, 61 bottles of beer.
Take one down and pass it around, 60 bottles of beer on the wall.

60 bottles of beer on the wall, 60 bottles of beer.
Take one down and pass it around, 59 bottles of beer on the wall.

59 bottles of beer on the wall, 59 bottles of beer.
Take one down and pass it around, 58 bottles of beer on the wall.

58 bottles of beer on the wall, 58 bottles of beer.
Take one down and pass it around, 57 bottles of beer on the wall.

57 bottles of beer on the wall, 57 bottles of beer.
Take one down and pass it around, 56 bottles of beer on the wall.

56 bottles of beer on the wall, 56 bottles of beer.
Take one down and pass it around, 55 bottles of beer on the wall.

55 bottles of beer on the wall, 55 bottles of beer.
Take one down and pass it around, 54 bottles of beer on the wall.

54 bottles of beer on the wall, 54 bottles of beer.
Take one down and pass it around, 53 bottles of beer on the wall.

53 bottles of beer on the wall, 53 bottles of beer.
Take one down and pass it around, 52 bottles of beer on the wall.

52 bottles of beer on the wall, 52 bottles of beer.
Take one down and pass it around, 51 bottles of beer on the wall.

51 bottles of beer on the wall, 51 bottles of beer.
Take one down and pass it around, 50 bottles of beer on the wall.

50 bottles of beer on the wall, 50 bottles of beer.
Take one down and pass it around, 49 bottles of beer on the wall.

49 bottles of beer on the wall, 49 bottles of beer.
Take one down and pass it around, 48 bottles of beer on the wall.

48 bottles of beer on the wall, 48 bottles of beer.
Take one down and pass it around, 47 bottles of beer on the wall.

47 bottles of beer on the wall, 47 bottles of beer.
Take one down and pass it around, 46 bottles of beer on the wall.

46 bottles of beer on the wall, 46 bottles of beer.
Take one down and pass it around, 45 bottles of beer on the wall.

45 bottles of beer on the wall, 45 bottles of beer.
Take one down and pass it around, 44 bottles of beer on the wall.

44 bottles of beer on the wall, 44 bottles of beer.
Take one down and pass it around, 43 bottles of beer on the wall.

43 bottles of beer on the wall, 43 bottles of beer.
Take one down and pass it around, 42 bottles of beer on the wall.

42 bottles of beer on the wall, 42 bottles of beer.
Take one down and pass it around, 41 bottles of beer on the wall.

41 bottles of beer on the wall, 41 bottles of beer.
Take one down and pass it around, 40 bottles of beer on the wall.

40 bottles of beer on the wall, 40 bottles of beer.
Take one down and pass it around, 39 bottles of beer on the wall.

39 bottles of beer on the wall, 39 bottles of beer.
Take one down and pass it around, 38 bottles of beer on the wall.

38 bottles of beer on the wall, 38 bottles of beer.
Take one down and pass it around, 37 bottles of beer on the wall.

37 bottles of beer on the wall, 37 bottles of beer.
Take one down and pass it around, 36 bottles of beer on the wall.

36 bottles of beer on the wall, 36 bottles of beer.
Take one down and pass it around, 35 bottles of beer on the wall.

35 bottles of beer on the wall, 35 bottles of beer.
Take one down and pass it around, 34 bottles of beer on the wall.

34 bottles of beer on the wall, 34 bottles of beer.
Take one down and pass it around, 33 bottles of beer on the wall.

33 bottles of beer on the wall, 33 bottles of beer.
Take one down and pass it around, 32 bottles of beer on the wall.

32 bottles of beer on the wall, 32 bottles of beer.
Take one down and pass it around, 31 bottles of beer on the wall.

31 bottles of beer on the wall, 31 bottles of beer.
Take one down and pass it around, 30 bottles of beer on the wall.

30 bottles of beer on the wall, 30 bottles of beer.
Take one down and pass it around, 29 bottles of beer on the wall.

29 bottles of beer on the wall, 29 bottles of beer.
Take one down and pass it around, 28 bottles of beer on the wall.

28 bottles of beer on the wall, 28 bottles of beer.
Take one down and pass it around, 27 bottles of beer on the wall.

27 bottles of beer on the wall, 27 bottles of beer.
Take one down and pass it around, 26 bottles of beer on the wall.

26 bottles of beer on the wall, 26 bottles of beer.
Take one down and pass it around, 25 bottles of beer on the wall.

25 bottles of beer on the wall, 25 bottles of beer.
Take one down and pass it around, 24 bottles of beer on the wall.

24 bottles of beer on the wall, 24 bottles of beer.
Take one down and pass it around, 23 bottles of beer on the wall.

23 bottles of beer on the wall, 23 bottles of beer.
Take one down and pass it around, 22 bottles of beer on the wall.

22 bottles of beer on the wall, 22 bottles of beer.
Take one down and pass it around, 21 bottles of beer on the wall.

21 bottles of beer on the wall, 21 bottles of beer.
Take one down and pass it around, 20 bottles of beer on the wall.

20 bottles of beer on the wall, 20 bottles of beer.
Take one down and pass it around, 19 bottles of beer on the wall.

19 bottles of beer on the wall, 19 bottles of beer.
Take one down and pass it around, 18 bottles of beer on the wall.

18 bottles of beer on the wall, 18 bottles of beer.
Take one down and pass it around, 17 bottles of beer on the wall.

17 bottles of beer on the wall, 17 bottles of beer.
Take one down and pass it around, 16 bottles of beer on the wall.

16 bottles of beer on the wall, 16 bottles of beer.
Take one down and pass it around, 15 bottles of beer on the wall.

15 bottles of beer on the wall, 15 bottles of beer.
Take one down and pass it around, 14 bottles of beer on the wall.

14 bottles of beer on the wall, 14 bottles of beer.
Take one down and pass it around, 13 bottles of beer on the wall.

13 bottles of beer on the wall, 13 bottles of beer.
Take one down and pass it around, 12 bottles of beer on the wall.

12 bottles of beer on the wall, 12 bottles of beer.
Take one down and pass it around, 11 bottles of beer on the wall.

11 bottles of beer on the wall, 11 bottles of beer.
Take one down and pass it around, 10 bottles of beer on the wall.

10 bottles of beer on the wall, 10 bottles of beer.
Take one down and pass it around, 9 bottles of beer on the wall.

9 bottles of beer on the wall, 9 bottles of beer.
Take one down and pass it around, 8 bottles of beer on the wall.

8 bottles of beer on the wall, 8 bottles of beer.
Take one down and pass it around, 7 bottles of beer on the wall.

7 bottles of beer on the wall, 7 bottles of beer.
Take one down and pass it around, 6 bottles of beer on the wall.

6 bottles of beer on the wall, 6 bottles of beer.
Take one down and pass it around, 5 bottles of beer on the wall.

5 bottles of beer on the wall, 5 bottles of beer.
Take one down and pass it around, 4 bottles of beer on the wall.

4 bottles of beer on the wall, 4 bottles of beer.
Take one down and pass it around, 3 bottles of beer on the wall.

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

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.

For bonus points

Did you get the tests passing and the code clean? If you want to, these are some additional things you could try:

  • Remove as much duplication as you possibly can.
  • Optimize for readability, even if it means introducing duplication.
  • If you've removed all the duplication, do you have a lot of conditionals? Try replacing the conditionals with polymorphism, if it applies in this language. How readable is it?

Then please share your thoughts in a comment on the submission. Did this experiment make the code better? Worse? Did you learn anything from it?


For installation and learning resources, refer to the Ruby resources page.

For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:

gem install minitest

If you would like color output, you can require 'minitest/pride' in the test file, or note the alternative instruction, below, for running the test file.

Run the tests from the exercise directory using the following command:

ruby beer_song_test.rb

To include color from the command line:

ruby -r minitest/pride beer_song_test.rb

Source

Learn to Program by Chris Pine http://pine.fm/LearnToProgram/?Chapter=06

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

beer_song_test.rb

require 'minitest/autorun'
require_relative 'beer_song'

# Common test data version: 2.1.0 87a334d
class BeerSongTest < Minitest::Test
  def test_first_generic_verse
    # skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.
    TEXT
    assert_equal expected, BeerSong.recite(99, 1)
  end

  def test_last_generic_verse
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    3 bottles of beer on the wall, 3 bottles of beer.
    Take one down and pass it around, 2 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(3, 1)
  end

  def test_verse_with_2_bottles
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.
    TEXT
    assert_equal expected, BeerSong.recite(2, 1)
  end

  def test_verse_with_1_bottle
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.
    TEXT
    assert_equal expected, BeerSong.recite(1, 1)
  end

  def test_verse_with_0_bottles
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.
    TEXT
    assert_equal expected, BeerSong.recite(0, 1)
  end

  def test_first_two_verses
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.
    TEXT
    assert_equal expected, BeerSong.recite(99, 2)
  end

  def test_last_three_verses
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.
    TEXT
    assert_equal expected, BeerSong.recite(2, 3)
  end

  def test_all_verses
    skip
    expected = <<-TEXT.gsub(/^ */, '')
    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.

    97 bottles of beer on the wall, 97 bottles of beer.
    Take one down and pass it around, 96 bottles of beer on the wall.

    96 bottles of beer on the wall, 96 bottles of beer.
    Take one down and pass it around, 95 bottles of beer on the wall.

    95 bottles of beer on the wall, 95 bottles of beer.
    Take one down and pass it around, 94 bottles of beer on the wall.

    94 bottles of beer on the wall, 94 bottles of beer.
    Take one down and pass it around, 93 bottles of beer on the wall.

    93 bottles of beer on the wall, 93 bottles of beer.
    Take one down and pass it around, 92 bottles of beer on the wall.

    92 bottles of beer on the wall, 92 bottles of beer.
    Take one down and pass it around, 91 bottles of beer on the wall.

    91 bottles of beer on the wall, 91 bottles of beer.
    Take one down and pass it around, 90 bottles of beer on the wall.

    90 bottles of beer on the wall, 90 bottles of beer.
    Take one down and pass it around, 89 bottles of beer on the wall.

    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.

    88 bottles of beer on the wall, 88 bottles of beer.
    Take one down and pass it around, 87 bottles of beer on the wall.

    87 bottles of beer on the wall, 87 bottles of beer.
    Take one down and pass it around, 86 bottles of beer on the wall.

    86 bottles of beer on the wall, 86 bottles of beer.
    Take one down and pass it around, 85 bottles of beer on the wall.

    85 bottles of beer on the wall, 85 bottles of beer.
    Take one down and pass it around, 84 bottles of beer on the wall.

    84 bottles of beer on the wall, 84 bottles of beer.
    Take one down and pass it around, 83 bottles of beer on the wall.

    83 bottles of beer on the wall, 83 bottles of beer.
    Take one down and pass it around, 82 bottles of beer on the wall.

    82 bottles of beer on the wall, 82 bottles of beer.
    Take one down and pass it around, 81 bottles of beer on the wall.

    81 bottles of beer on the wall, 81 bottles of beer.
    Take one down and pass it around, 80 bottles of beer on the wall.

    80 bottles of beer on the wall, 80 bottles of beer.
    Take one down and pass it around, 79 bottles of beer on the wall.

    79 bottles of beer on the wall, 79 bottles of beer.
    Take one down and pass it around, 78 bottles of beer on the wall.

    78 bottles of beer on the wall, 78 bottles of beer.
    Take one down and pass it around, 77 bottles of beer on the wall.

    77 bottles of beer on the wall, 77 bottles of beer.
    Take one down and pass it around, 76 bottles of beer on the wall.

    76 bottles of beer on the wall, 76 bottles of beer.
    Take one down and pass it around, 75 bottles of beer on the wall.

    75 bottles of beer on the wall, 75 bottles of beer.
    Take one down and pass it around, 74 bottles of beer on the wall.

    74 bottles of beer on the wall, 74 bottles of beer.
    Take one down and pass it around, 73 bottles of beer on the wall.

    73 bottles of beer on the wall, 73 bottles of beer.
    Take one down and pass it around, 72 bottles of beer on the wall.

    72 bottles of beer on the wall, 72 bottles of beer.
    Take one down and pass it around, 71 bottles of beer on the wall.

    71 bottles of beer on the wall, 71 bottles of beer.
    Take one down and pass it around, 70 bottles of beer on the wall.

    70 bottles of beer on the wall, 70 bottles of beer.
    Take one down and pass it around, 69 bottles of beer on the wall.

    69 bottles of beer on the wall, 69 bottles of beer.
    Take one down and pass it around, 68 bottles of beer on the wall.

    68 bottles of beer on the wall, 68 bottles of beer.
    Take one down and pass it around, 67 bottles of beer on the wall.

    67 bottles of beer on the wall, 67 bottles of beer.
    Take one down and pass it around, 66 bottles of beer on the wall.

    66 bottles of beer on the wall, 66 bottles of beer.
    Take one down and pass it around, 65 bottles of beer on the wall.

    65 bottles of beer on the wall, 65 bottles of beer.
    Take one down and pass it around, 64 bottles of beer on the wall.

    64 bottles of beer on the wall, 64 bottles of beer.
    Take one down and pass it around, 63 bottles of beer on the wall.

    63 bottles of beer on the wall, 63 bottles of beer.
    Take one down and pass it around, 62 bottles of beer on the wall.

    62 bottles of beer on the wall, 62 bottles of beer.
    Take one down and pass it around, 61 bottles of beer on the wall.

    61 bottles of beer on the wall, 61 bottles of beer.
    Take one down and pass it around, 60 bottles of beer on the wall.

    60 bottles of beer on the wall, 60 bottles of beer.
    Take one down and pass it around, 59 bottles of beer on the wall.

    59 bottles of beer on the wall, 59 bottles of beer.
    Take one down and pass it around, 58 bottles of beer on the wall.

    58 bottles of beer on the wall, 58 bottles of beer.
    Take one down and pass it around, 57 bottles of beer on the wall.

    57 bottles of beer on the wall, 57 bottles of beer.
    Take one down and pass it around, 56 bottles of beer on the wall.

    56 bottles of beer on the wall, 56 bottles of beer.
    Take one down and pass it around, 55 bottles of beer on the wall.

    55 bottles of beer on the wall, 55 bottles of beer.
    Take one down and pass it around, 54 bottles of beer on the wall.

    54 bottles of beer on the wall, 54 bottles of beer.
    Take one down and pass it around, 53 bottles of beer on the wall.

    53 bottles of beer on the wall, 53 bottles of beer.
    Take one down and pass it around, 52 bottles of beer on the wall.

    52 bottles of beer on the wall, 52 bottles of beer.
    Take one down and pass it around, 51 bottles of beer on the wall.

    51 bottles of beer on the wall, 51 bottles of beer.
    Take one down and pass it around, 50 bottles of beer on the wall.

    50 bottles of beer on the wall, 50 bottles of beer.
    Take one down and pass it around, 49 bottles of beer on the wall.

    49 bottles of beer on the wall, 49 bottles of beer.
    Take one down and pass it around, 48 bottles of beer on the wall.

    48 bottles of beer on the wall, 48 bottles of beer.
    Take one down and pass it around, 47 bottles of beer on the wall.

    47 bottles of beer on the wall, 47 bottles of beer.
    Take one down and pass it around, 46 bottles of beer on the wall.

    46 bottles of beer on the wall, 46 bottles of beer.
    Take one down and pass it around, 45 bottles of beer on the wall.

    45 bottles of beer on the wall, 45 bottles of beer.
    Take one down and pass it around, 44 bottles of beer on the wall.

    44 bottles of beer on the wall, 44 bottles of beer.
    Take one down and pass it around, 43 bottles of beer on the wall.

    43 bottles of beer on the wall, 43 bottles of beer.
    Take one down and pass it around, 42 bottles of beer on the wall.

    42 bottles of beer on the wall, 42 bottles of beer.
    Take one down and pass it around, 41 bottles of beer on the wall.

    41 bottles of beer on the wall, 41 bottles of beer.
    Take one down and pass it around, 40 bottles of beer on the wall.

    40 bottles of beer on the wall, 40 bottles of beer.
    Take one down and pass it around, 39 bottles of beer on the wall.

    39 bottles of beer on the wall, 39 bottles of beer.
    Take one down and pass it around, 38 bottles of beer on the wall.

    38 bottles of beer on the wall, 38 bottles of beer.
    Take one down and pass it around, 37 bottles of beer on the wall.

    37 bottles of beer on the wall, 37 bottles of beer.
    Take one down and pass it around, 36 bottles of beer on the wall.

    36 bottles of beer on the wall, 36 bottles of beer.
    Take one down and pass it around, 35 bottles of beer on the wall.

    35 bottles of beer on the wall, 35 bottles of beer.
    Take one down and pass it around, 34 bottles of beer on the wall.

    34 bottles of beer on the wall, 34 bottles of beer.
    Take one down and pass it around, 33 bottles of beer on the wall.

    33 bottles of beer on the wall, 33 bottles of beer.
    Take one down and pass it around, 32 bottles of beer on the wall.

    32 bottles of beer on the wall, 32 bottles of beer.
    Take one down and pass it around, 31 bottles of beer on the wall.

    31 bottles of beer on the wall, 31 bottles of beer.
    Take one down and pass it around, 30 bottles of beer on the wall.

    30 bottles of beer on the wall, 30 bottles of beer.
    Take one down and pass it around, 29 bottles of beer on the wall.

    29 bottles of beer on the wall, 29 bottles of beer.
    Take one down and pass it around, 28 bottles of beer on the wall.

    28 bottles of beer on the wall, 28 bottles of beer.
    Take one down and pass it around, 27 bottles of beer on the wall.

    27 bottles of beer on the wall, 27 bottles of beer.
    Take one down and pass it around, 26 bottles of beer on the wall.

    26 bottles of beer on the wall, 26 bottles of beer.
    Take one down and pass it around, 25 bottles of beer on the wall.

    25 bottles of beer on the wall, 25 bottles of beer.
    Take one down and pass it around, 24 bottles of beer on the wall.

    24 bottles of beer on the wall, 24 bottles of beer.
    Take one down and pass it around, 23 bottles of beer on the wall.

    23 bottles of beer on the wall, 23 bottles of beer.
    Take one down and pass it around, 22 bottles of beer on the wall.

    22 bottles of beer on the wall, 22 bottles of beer.
    Take one down and pass it around, 21 bottles of beer on the wall.

    21 bottles of beer on the wall, 21 bottles of beer.
    Take one down and pass it around, 20 bottles of beer on the wall.

    20 bottles of beer on the wall, 20 bottles of beer.
    Take one down and pass it around, 19 bottles of beer on the wall.

    19 bottles of beer on the wall, 19 bottles of beer.
    Take one down and pass it around, 18 bottles of beer on the wall.

    18 bottles of beer on the wall, 18 bottles of beer.
    Take one down and pass it around, 17 bottles of beer on the wall.

    17 bottles of beer on the wall, 17 bottles of beer.
    Take one down and pass it around, 16 bottles of beer on the wall.

    16 bottles of beer on the wall, 16 bottles of beer.
    Take one down and pass it around, 15 bottles of beer on the wall.

    15 bottles of beer on the wall, 15 bottles of beer.
    Take one down and pass it around, 14 bottles of beer on the wall.

    14 bottles of beer on the wall, 14 bottles of beer.
    Take one down and pass it around, 13 bottles of beer on the wall.

    13 bottles of beer on the wall, 13 bottles of beer.
    Take one down and pass it around, 12 bottles of beer on the wall.

    12 bottles of beer on the wall, 12 bottles of beer.
    Take one down and pass it around, 11 bottles of beer on the wall.

    11 bottles of beer on the wall, 11 bottles of beer.
    Take one down and pass it around, 10 bottles of beer on the wall.

    10 bottles of beer on the wall, 10 bottles of beer.
    Take one down and pass it around, 9 bottles of beer on the wall.

    9 bottles of beer on the wall, 9 bottles of beer.
    Take one down and pass it around, 8 bottles of beer on the wall.

    8 bottles of beer on the wall, 8 bottles of beer.
    Take one down and pass it around, 7 bottles of beer on the wall.

    7 bottles of beer on the wall, 7 bottles of beer.
    Take one down and pass it around, 6 bottles of beer on the wall.

    6 bottles of beer on the wall, 6 bottles of beer.
    Take one down and pass it around, 5 bottles of beer on the wall.

    5 bottles of beer on the wall, 5 bottles of beer.
    Take one down and pass it around, 4 bottles of beer on the wall.

    4 bottles of beer on the wall, 4 bottles of beer.
    Take one down and pass it around, 3 bottles of beer on the wall.

    3 bottles of beer on the wall, 3 bottles of beer.
    Take one down and pass it around, 2 bottles of beer on the wall.

    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.
    TEXT
    assert_equal expected, BeerSong.recite(99, 100)
  end
end
class String
  def pluralize(n)
    if n == 1
      self
    else
      "#{self}s"
    end
  end
end

class BeerSongVerse
  attr_reader :n

  def initialize(n)
    @n = n
  end

  def to_s
    if n == 0
      recite_zero
    elsif n == 1
      recite_one
    else
      recite_many
    end
  end

  private

  def recite_zero
    <<~TEXT
    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.
    TEXT
  end

  def recite_one
    <<~TEXT
    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.
    TEXT
  end

  def recite_many
    bottles_left = "bottle".pluralize(n-1)
    <<~TEXT
    #{n} bottles of beer on the wall, #{n} bottles of beer.
    Take one down and pass it around, #{n-1} #{bottles_left} of beer on the wall.
    TEXT
  end
end

class BeerSong
  def self.recite(count, n)
    return if n == 0
    [BeerSongVerse.new(count), BeerSong.recite(count-1, n-1)].compact.join("\n")
  end
end

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