diff --git a/Library/Homebrew/cmd/diy.rb b/Library/Homebrew/cmd/diy.rb
index 2e71f8890c..174626afcc 100644
--- a/Library/Homebrew/cmd/diy.rb
+++ b/Library/Homebrew/cmd/diy.rb
@@ -21,7 +21,7 @@ module Homebrew extend self
       end
     end
 
-    prefix = HOMEBREW_CELLAR+name+version
+    prefix = HOMEBREW_CELLAR/name/version
 
     if File.file? 'CMakeLists.txt'
       puts "-DCMAKE_INSTALL_PREFIX=#{prefix}"
diff --git a/Library/Homebrew/cmd/versions.rb b/Library/Homebrew/cmd/versions.rb
index 2675511064..f5fd72ea2e 100644
--- a/Library/Homebrew/cmd/versions.rb
+++ b/Library/Homebrew/cmd/versions.rb
@@ -13,7 +13,7 @@ module Homebrew extend self
       else
         f.versions do |version, sha|
           print Tty.white.to_s
-          print "#{version.ljust(8)} "
+          print "#{version.to_s.ljust(8)} "
           print Tty.reset.to_s
           puts "git checkout #{sha} #{f.pretty_relative_path}"
         end
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index dec937c54a..8009e98eee 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -163,8 +163,7 @@ class Pathname
 
   def version
     require 'version'
-    version = Version.parse(self)
-    version.to_s unless version.nil?
+    Version.parse(self)
   end
 
   def compression_type
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index bf7c4f3356..d6f9f8f7b8 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -108,7 +108,7 @@ class Formula
   def prefix
     validate_variable :name
     validate_variable :version
-    HOMEBREW_CELLAR+@name+@version
+    HOMEBREW_CELLAR/@name/@version
   end
   def rack; prefix.parent end
 
@@ -543,7 +543,7 @@ private
 
   def validate_variable name
     v = instance_variable_get("@#{name}")
-    raise "Invalid @#{name}" if v.to_s.empty? or v =~ /\s/
+    raise "Invalid @#{name}" if v.to_s.empty? or v.to_s =~ /\s/
   end
 
   def set_instance_variable(type)
diff --git a/Library/Homebrew/formula_support.rb b/Library/Homebrew/formula_support.rb
index 2119fbd116..1b968d8499 100644
--- a/Library/Homebrew/formula_support.rb
+++ b/Library/Homebrew/formula_support.rb
@@ -1,5 +1,6 @@
 require 'download_strategy'
 require 'checksums'
+require 'version'
 
 class SoftwareSpec
   attr_reader :checksum, :mirrors, :specs
@@ -58,12 +59,12 @@ class SoftwareSpec
   end
 
   def version val=nil
-    unless val.nil?
-      @version = val
+    if val.nil?
+      @version ||= Version.parse(@url)
+    else
+      @version = Version.new(val)
       @explicit_version = true
     end
-    @version ||= Pathname.new(@url).version
-    return @version
   end
 
   def mirror val
@@ -73,7 +74,7 @@ class SoftwareSpec
 end
 
 class HeadSoftwareSpec < SoftwareSpec
-  def initialize url=nil, version='HEAD'
+  def initialize url=nil, version=Version.new(:HEAD)
     super
   end
 
@@ -120,7 +121,7 @@ class Bottle < SoftwareSpec
   # as accessor for @version to preserve the interface
   def version val=nil
     if val.nil?
-      return @version ||= Pathname.new(@url).version
+      return @version ||= Version.parse(@url)
     else
       @revision = val
     end
diff --git a/Library/Homebrew/test/test_bucket.rb b/Library/Homebrew/test/test_bucket.rb
index 0758d26232..2963a5532b 100644
--- a/Library/Homebrew/test/test_bucket.rb
+++ b/Library/Homebrew/test/test_bucket.rb
@@ -22,6 +22,8 @@ end
 # separate TestCase classes.
 
 class BeerTasting < Test::Unit::TestCase
+  include VersionAssertions
+
   def test_supported_compressed_types
     assert_nothing_raised do
       MockFormula.new 'test-0.1.tar.gz'
@@ -129,12 +131,6 @@ class BeerTasting < Test::Unit::TestCase
     assert_equal 10.7, f+0.1
   end
 
-  def test_pathname_version
-    d=HOMEBREW_CELLAR+'foo-0.1.9'
-    d.mkpath
-    assert_equal '0.1.9', d.version
-  end
-
   def test_pathname_plus_yeast
     nostdout do
       assert_nothing_raised do
@@ -176,12 +172,12 @@ class BeerTasting < Test::Unit::TestCase
 
     assert_equal '.tar.gz', foo1.extname
     assert_equal 'foo-0.1', foo1.stem
-    assert_equal '0.1', foo1.version
+    assert_version_equal '0.1', foo1.version
 
     foo1 = HOMEBREW_CACHE/'foo-0.1.cpio.gz'
     assert_equal '.cpio.gz', foo1.extname
     assert_equal 'foo-0.1', foo1.stem
-    assert_equal '0.1', foo1.version
+    assert_version_equal '0.1', foo1.version
   end
 
   class MockMockFormula < Struct.new(:name); end
diff --git a/Library/Homebrew/test/test_formula.rb b/Library/Homebrew/test/test_formula.rb
index 686d8b0f07..e60ddd0514 100644
--- a/Library/Homebrew/test/test_formula.rb
+++ b/Library/Homebrew/test/test_formula.rb
@@ -10,6 +10,7 @@ class MostlyAbstractFormula < Formula
 end
 
 class FormulaTests < Test::Unit::TestCase
+  include VersionAssertions
 
   def test_prefix
     nostdout do
@@ -65,7 +66,7 @@ class FormulaTests < Test::Unit::TestCase
     assert_equal 'http://example.com', f.homepage
     assert_equal 'file:///foo.com/testball-0.1.tbz', f.url
     assert_equal 1, f.mirrors.length
-    assert_equal '0.1', f.version
+    assert_version_equal '0.1', f.version
     assert_equal f.stable, f.active_spec
     assert_equal CurlDownloadStrategy, f.download_strategy
     assert_instance_of CurlDownloadStrategy, f.downloader
@@ -124,10 +125,10 @@ class FormulaTests < Test::Unit::TestCase
     assert !f.stable.explicit_version?
     assert !f.bottle.explicit_version?
     assert !f.devel.explicit_version?
-    assert_equal '0.1', f.stable.version
-    assert_equal '0.1', f.bottle.version
-    assert_equal '0.2', f.devel.version
-    assert_equal 'HEAD', f.head.version
+    assert_version_equal '0.1', f.stable.version
+    assert_version_equal '0.1', f.bottle.version
+    assert_version_equal '0.2', f.devel.version
+    assert_version_equal 'HEAD', f.head.version
     assert_equal 0, f.bottle.revision
   end
 
@@ -135,7 +136,7 @@ class FormulaTests < Test::Unit::TestCase
     ARGV.push '--devel'
     f = SpecTestBall.new
     assert_equal f.devel, f.active_spec
-    assert_equal '0.2', f.version
+    assert_version_equal '0.2', f.version
     assert_equal 'file:///foo.com/testball-0.2.tbz', f.url
     assert_equal CurlDownloadStrategy, f.download_strategy
     assert_instance_of CurlDownloadStrategy, f.downloader
@@ -146,7 +147,7 @@ class FormulaTests < Test::Unit::TestCase
     ARGV.push '--HEAD'
     f = SpecTestBall.new
     assert_equal f.head, f.active_spec
-    assert_equal 'HEAD', f.version
+    assert_version_equal 'HEAD', f.version
     assert_equal 'https://github.com/mxcl/homebrew.git', f.url
     assert_equal GitDownloadStrategy, f.download_strategy
     assert_instance_of GitDownloadStrategy, f.downloader
@@ -155,9 +156,9 @@ class FormulaTests < Test::Unit::TestCase
 
   def test_explicit_version_spec
     f = ExplicitVersionSpecTestBall.new
-    assert_equal '0.3', f.version
-    assert_equal '0.3', f.stable.version
-    assert_equal '0.4', f.devel.version
+    assert_version_equal '0.3', f.version
+    assert_version_equal '0.3', f.stable.version
+    assert_version_equal '0.4', f.devel.version
     assert f.stable.explicit_version?
     assert f.devel.explicit_version?
   end
@@ -183,7 +184,7 @@ class FormulaTests < Test::Unit::TestCase
 
       assert !f.bottle.explicit_version?
       assert_equal 0, f.bottle.revision
-      assert_equal '0.1', f.bottle.version
+      assert_version_equal '0.1', f.bottle.version
     else
       assert_nil f.bottle
     end
@@ -203,7 +204,7 @@ class FormulaTests < Test::Unit::TestCase
     assert_nil f.devel
 
     assert_equal f.head, f.active_spec
-    assert_equal 'HEAD', f.version
+    assert_version_equal 'HEAD', f.version
     assert_nil f.head.checksum
     assert_equal 'https://github.com/mxcl/homebrew.git', f.url
     assert_equal GitDownloadStrategy, f.download_strategy
@@ -220,7 +221,7 @@ class FormulaTests < Test::Unit::TestCase
     assert_nil f.devel
 
     assert_equal f.head, f.active_spec
-    assert_equal 'HEAD', f.version
+    assert_version_equal 'HEAD', f.version
     assert_nil f.head.checksum
     assert_equal 'https://github.com/mxcl/homebrew.git', f.url
     assert_equal GitDownloadStrategy, f.download_strategy
@@ -237,7 +238,7 @@ class FormulaTests < Test::Unit::TestCase
     assert_nil f.devel
 
     assert_equal f.head, f.active_spec
-    assert_equal 'HEAD', f.version
+    assert_version_equal 'HEAD', f.version
     assert_nil f.head.checksum
     assert_equal 'https://github.com/mxcl/homebrew.git', f.url
     assert_equal GitDownloadStrategy, f.download_strategy
diff --git a/Library/Homebrew/test/test_versions.rb b/Library/Homebrew/test/test_versions.rb
index a432b1824e..ab6f83991b 100644
--- a/Library/Homebrew/test/test_versions.rb
+++ b/Library/Homebrew/test/test_versions.rb
@@ -3,20 +3,6 @@ require 'formula'
 require 'test/testball'
 require 'version'
 
-module VersionAssertions
-  def assert_version_detected expected, url
-    assert_equal expected, Version.parse(url).to_s
-  end
-
-  def assert_version_nil url
-    assert_nil Version.parse(url)
-  end
-
-  def assert_version_comparison a, comparison, b
-    eval "assert Version.new(a) #{comparison} Version.new(b)"
-  end
-end
-
 class TestBadVersion < TestBall
   def initialize name=nil
     @stable = SoftwareSpec.new
@@ -34,6 +20,9 @@ class VersionComparisonTests < Test::Unit::TestCase
     assert_version_comparison '1.2.3', '>', '1.2.2'
     assert_version_comparison '1.2.3-p34', '>', '1.2.3-p33'
     assert_version_comparison '1.2.4', '<', '1.2.4.1'
+    assert_version_comparison 'HEAD', '==', 'HEAD'
+    assert_version_comparison 'HEAD', '>', '1.2.3'
+    assert_version_comparison '1.2.3', '<', 'HEAD'
   end
 end
 
@@ -43,7 +32,7 @@ class VersionParsingTests < Test::Unit::TestCase
   def test_pathname_version
     d = HOMEBREW_CELLAR/'foo-0.1.9'
     d.mkpath
-    assert_equal '0.1.9', d.version
+    assert_version_equal '0.1.9', d.version
   end
 
   def test_no_version
diff --git a/Library/Homebrew/test/testing_env.rb b/Library/Homebrew/test/testing_env.rb
index b01fe22956..d0dbd9401b 100644
--- a/Library/Homebrew/test/testing_env.rb
+++ b/Library/Homebrew/test/testing_env.rb
@@ -65,3 +65,21 @@ ARGV.extend(HomebrewArgvExtension)
 
 require 'extend/ENV'
 ENV.extend(HomebrewEnvExtension)
+
+module VersionAssertions
+  def assert_version_equal expected, actual
+    assert_equal Version.new(expected), actual
+  end
+
+  def assert_version_detected expected, url
+    assert_equal expected, Version.parse(url).to_s
+  end
+
+  def assert_version_nil url
+    assert_nil Version.parse(url)
+  end
+
+  def assert_version_comparison a, comparison, b
+    eval "assert Version.new(a) #{comparison} Version.new(b)"
+  end
+end