Incorporate minimum value into 99 Bottles verse

lib/bottles.rb

@@ -15,7 +15,7 @@ def verses(upper, lower)
   end
 
   def verse(number)
-    verse_template.lyrics(number, max: max)
+    verse_template.lyrics(number, max: max, min: min)
   end
 end
 
@@ -30,8 +30,8 @@ def min
       0
     end
 
-    def lyrics(number, max: self.max)
-      new(BottleNumber.for(number, max: max)).lyrics
+    def lyrics(number, max: self.max, min: self.min)
+      new(BottleNumber.for(number, max: max, min: min)).lyrics
     end
   end
 
@@ -51,8 +51,8 @@ def lyrics
 
 
 class BottleNumber
-  def self.for(number, max:)
-    case number
+  def self.for(number, max:, min:)
+    bottle_number = case number
     when 0
       BottleNumber0
     when 1
@@ -61,13 +61,25 @@ def self.for(number, max:)
       BottleNumber6
     else
       BottleNumber
-    end.new(number, max: max)
+    end.new(number, max: max, min: min)
+
+    if (number == min)
+      BottleNumberMin.new(
+        number,
+        max: max,
+        min: min,
+        bottle_number: bottle_number
+      )
+    else
+      bottle_number
+    end
   end
 
-  attr_reader :number, :max
-  def initialize(number, max:)
+  attr_reader :number, :max, :min
+  def initialize(number, max:, min:)
     @number = number
     @max = max
+    @min = min
   end
 
   def to_s
@@ -91,22 +103,14 @@ def pronoun
   end
 
   def successor
-    BottleNumber.for(number - 1, max: max)
+    BottleNumber.for(number - 1, max: max, min: min)
   end
 end
 
 class BottleNumber0 < BottleNumber
   def quantity
     "no more"
   end
-
-  def action
-    "Go to the store and buy some more"
-  end
-
-  def successor
-    BottleNumber.for(max, max: max)
-  end
 end
 
 class BottleNumber1 < BottleNumber
@@ -128,3 +132,26 @@ def container
     "six-pack"
   end
 end
+
+class BottleNumberMin < BottleNumber
+  def initialize(number, max:, min:, bottle_number:)
+    super(number, max: max, min: min)
+    @bottle_number = bottle_number
+  end
+
+  def quantity
+    @bottle_number.quantity
+  end
+
+  def container
+    @bottle_number.container
+  end
+
+  def action
+    "Go to the store and buy some more"
+  end
+
+  def successor
+    BottleNumber.for(max, max: max, min: min)
+  end
+end

test/bottles_test.rb

@@ -21,7 +21,7 @@ def min
       5
     end
 
-    def lyrics(number, max: nil)
+    def lyrics(number, max: nil, min: nil)
       "This is verse #{number}.\n"
     end
   end
@@ -97,6 +97,15 @@ def test_verse_1
      assert_equal expected, BottleVerse.lyrics(1)
   end
 
+  def test_verse_1_with_explicit_min_value
+    expected =
+      "1 bottle of beer on the wall, " +
+      "1 bottle of beer.\n" +
+      "Go to the store and buy some more, " +
+      "99 bottles of beer on the wall.\n"
+     assert_equal expected, BottleVerse.lyrics(1, min: 1)
+  end
+
   def test_verse_0
     expected =
       "No more bottles of beer on the wall, " +
@@ -116,6 +125,39 @@ def test_verse_0_with_explicit_max_value
   end
 end
 
+class BottleNumberMinTest < Minitest::Test
+  def test_verse_1
+    expected =
+      "1 bottle of beer on the wall, " +
+      "1 bottle of beer.\n" +
+      "Go to the store and buy some more, " +
+      "99 bottles of beer on the wall.\n"
+    assert_equal expected, BottleVerse.new(
+      BottleNumberMin.new(
+        1,
+        max: 99,
+        min: 1,
+        bottle_number: BottleNumber.for(1, max: 99, min: 1)
+      )
+    ).lyrics
+  end
+
+  def test_verse_0
+    expected =
+      "No more bottles of beer on the wall, " +
+      "no more bottles of beer.\n" +
+      "Go to the store and buy some more, " +
+      "1 six-pack of beer on the wall.\n"
+    assert_equal expected, BottleVerse.new(
+      BottleNumberMin.new(
+        0,
+        max: 6,
+        min: 0,
+        bottle_number: BottleNumber.for(0, max: 6, min: 0)
+      )
+    ).lyrics
+  end
+end
 
 class CountdownSongTest < Minitest::Test
   def test_verse
@@ -181,7 +223,7 @@ def test_song
 end
 
 class Bottles99IntegrationTest < Minitest::Test
-  def test_partial_7_bottles_song
+  def test_custom_max_bottles_song
     expected = <<-SONG
 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.
@@ -212,8 +254,38 @@ def test_partial_7_bottles_song
       expected,
       CountdownSong.new(
         verse_template: BottleVerse,
-        max: 7,
-        min: 0
+        max: 7
+      ).song
+    )
+  end
+
+  def test_custom_max_min_bottles_song
+    expected = <<-SONG
+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.
+
+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.
+Go to the store and buy some more, 1 six-pack of beer on the wall.
+    SONG
+
+    assert_equal(
+      expected,
+      CountdownSong.new(
+        verse_template: BottleVerse,
+        max: 6,
+        min: 1
       ).song
     )
   end