diff --git a/Library/Homebrew/bottles.rb b/Library/Homebrew/bottles.rb
index 7d9545f3802e0d2ceb5c28fdb354a6366728c189..e043df2b07289fd41b8e08a744df3e8e9912d730 100644
--- a/Library/Homebrew/bottles.rb
+++ b/Library/Homebrew/bottles.rb
@@ -81,9 +81,9 @@ end
 
 def bottle_tag
   case MacOS.version
-  when 10.8, 10.7, 10.5
+  when "10.8", "10.7", "10.5"
     MacOS.cat
-  when 10.6
+  when "10.6"
     Hardware::CPU.is_64_bit? ? :snow_leopard : :snow_leopard_32
   else
     Hardware::CPU.type == :ppc ? Hardware::CPU.family : MacOS.cat
diff --git a/Library/Homebrew/macos.rb b/Library/Homebrew/macos.rb
index 91c2050e8af7a465aa00043b26aec3dc487f82b8..54cf4348774effd9a2d53cb74083d2796d31559e 100644
--- a/Library/Homebrew/macos.rb
+++ b/Library/Homebrew/macos.rb
@@ -11,11 +11,11 @@ module MacOS extend self
 
   def cat
     case MacOS.version
-    when 10.8 then :mountain_lion
-    when 10.7 then :lion
-    when 10.6 then :snow_leopard
-    when 10.5 then :leopard
-    when 10.4 then :tiger
+    when "10.8" then :mountain_lion
+    when "10.7" then :lion
+    when "10.6" then :snow_leopard
+    when "10.5" then :leopard
+    when "10.4" then :tiger
     end
   end
 
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index eaae6fbf880a185885f3b8333d63ba394d7a3450..3fdd90463047a403619ff8c1784fd8a7a826d9f3 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -19,11 +19,11 @@ module MacOS::Xcode extend self
 
   def latest_version
     case MacOS.version
-    when 10.4       then "2.5"
-    when 10.5       then "3.1.4"
-    when 10.6       then "3.2.6"
-    when 10.7, 10.8 then "4.6.3"
-    when 10.9       then "5.0"
+    when "10.4"         then "2.5"
+    when "10.5"         then "3.1.4"
+    when "10.6"         then "3.2.6"
+    when "10.7", "10.8" then "4.6.3"
+    when "10.9"         then "5.0"
     else
       # Default to newest known version of Xcode for unreleased OSX versions.
       if MacOS.version > 10.9
diff --git a/Library/Homebrew/test/test_bottle_tag.rb b/Library/Homebrew/test/test_bottle_tag.rb
index 2b039a29fdc57ed494c409fa87025529e310c6bc..3dc51943a8838d212eca787419f131fea49b7ca9 100644
--- a/Library/Homebrew/test/test_bottle_tag.rb
+++ b/Library/Homebrew/test/test_bottle_tag.rb
@@ -3,42 +3,42 @@ require 'bottles'
 
 class BottleTagTests < Test::Unit::TestCase
   def test_cat_tiger_ppc
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.4))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.4"))
     Hardware::CPU.stubs(:type).returns(:ppc)
     Hardware::CPU.stubs(:family).returns(:foo)
     assert_equal :foo, bottle_tag
   end
 
   def test_cat_tiger_intel
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.4))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.4"))
     Hardware::CPU.stubs(:type).returns(:intel)
     assert_equal :tiger, bottle_tag
   end
 
   def test_cat_leopard
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.5))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.5"))
     assert_equal :leopard, bottle_tag
   end
 
   def test_cat_snow_leopard_32
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.6))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.6"))
     Hardware::CPU.stubs(:is_64_bit?).returns(false)
     assert_equal :snow_leopard_32, bottle_tag
   end
 
   def test_cat_snow_leopard_64
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.6))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.6"))
     Hardware::CPU.stubs(:is_64_bit?).returns(true)
     assert_equal :snow_leopard, bottle_tag
   end
 
   def test_cat_lion
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.7))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.7"))
     assert_equal :lion, bottle_tag
   end
 
   def test_cat_mountain_lion
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.8))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.8"))
     assert_equal :mountain_lion, bottle_tag
   end
 end
diff --git a/Library/Homebrew/test/test_dependency_collector.rb b/Library/Homebrew/test/test_dependency_collector.rb
index 0b4c19ebf7126d27361822fedfdba7b0cb8d95af..dafc83da095958dcb37afa07e6a87b3beac439ca 100644
--- a/Library/Homebrew/test/test_dependency_collector.rb
+++ b/Library/Homebrew/test/test_dependency_collector.rb
@@ -102,22 +102,22 @@ class DependencyCollectorTests < Test::Unit::TestCase
   end
 
   def test_x11_proxy_dep_mountain_lion
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.8))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.8"))
     assert_equal Dependency.new("libpng"), @d.build(:libpng)
   end
 
   def test_x11_proxy_dep_lion_or_older
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.7))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.7"))
     assert_equal X11Dependency::Proxy.new(:libpng), @d.build(:libpng)
   end
 
   def test_ld64_dep_pre_leopard
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.4))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.4"))
     assert_equal LD64Dependency.new, @d.build(:ld64)
   end
 
   def test_ld64_dep_leopard_or_newer
-    MacOS.stubs(:version).returns(MacOS::Version.new(10.5))
+    MacOS.stubs(:version).returns(MacOS::Version.new("10.5"))
     assert_nil @d.build(:ld64)
   end
 
diff --git a/Library/Homebrew/test/test_version_subclasses.rb b/Library/Homebrew/test/test_version_subclasses.rb
index 6b18246ba288aa0e9472b340ce2f52bf0157b7de..546fcadaa77f61c88b57e092de3ea2a53a1d8a2d 100644
--- a/Library/Homebrew/test/test_version_subclasses.rb
+++ b/Library/Homebrew/test/test_version_subclasses.rb
@@ -4,7 +4,7 @@ require 'os/mac/version'
 
 class MacOSVersionTests < Test::Unit::TestCase
   def setup
-    @v = MacOS::Version.new(10.7)
+    @v = MacOS::Version.new("10.7")
   end
 
   def test_compare_with_symbol
@@ -34,9 +34,9 @@ class MacOSVersionTests < Test::Unit::TestCase
   end
 
   def test_compare_with_version
-    assert_operator @v, :>, Version.new(10.6)
-    assert_operator @v, :==, Version.new(10.7)
-    assert_operator @v, :===, Version.new(10.7)
-    assert_operator @v, :<, Version.new(10.8)
+    assert_operator @v, :>, Version.new("10.6")
+    assert_operator @v, :==, Version.new("10.7")
+    assert_operator @v, :===, Version.new("10.7")
+    assert_operator @v, :<, Version.new("10.8")
   end
 end