付强的解法, 简单粗暴

lib/bottles.rb

@@ -0,0 +1,34 @@
+class Bottles
+  def verse(number)
+    case number
+    when 0
+      'No more bottles of beer on the wall, ' \
+        "no more bottles of beer.\n" \
+        'Go to the store and buy some more, ' \
+        "99 bottles of beer on the wall.\n"
+    when 1
+      '1 bottle of beer on the wall, ' \
+        "1 bottle of beer.\n" \
+        'Take it down and pass it around, ' \
+        "no more bottles of beer on the wall.\n"
+    when 2
+      '2 bottles of beer on the wall, ' \
+        "2 bottles of beer.\n" \
+        'Take one down and pass it around, ' \
+        "1 bottle of beer on the wall.\n"
+    else
+      "#{number} bottles of beer on the wall, " \
+        "#{number} bottles of beer.\n" \
+        'Take one down and pass it around, ' \
+        "#{number - 1} bottles of beer on the wall.\n"
+    end
+  end
+
+  def verses(from, to)
+    from.downto(to).map { |e| verse(e) }.join("\n")
+  end
+
+  def song
+    verses(99, 0)
+  end
+end

test/bottles_test.rb

@@ -12,7 +12,6 @@ def test_the_first_verse
   end
 
   def test_another_verse
-    skip
     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.
@@ -21,7 +20,6 @@ def test_another_verse
   end
 
   def test_verse_2
-    skip
     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.
@@ -30,7 +28,6 @@ def test_verse_2
   end
 
   def test_verse_1
-    skip
     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.
@@ -39,7 +36,6 @@ def test_verse_1
   end
 
   def test_verse_0
-    skip
     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.
@@ -48,7 +44,6 @@ def test_verse_0
   end
 
   def test_a_couple_verses
-    skip
     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.
@@ -60,7 +55,6 @@ def test_a_couple_verses
   end
 
   def test_a_few_verses
-    skip
     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.
@@ -75,7 +69,6 @@ def test_a_few_verses
   end
 
   def test_the_whole_song
-    skip
     expected = <<-SONG
 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.