diff --git a/.travis.yml b/.travis.yml
index 3bb2dc2d..a388edde 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,4 +4,4 @@ rvm:
   - jruby
   - rbx
   - ree
-script: "bundle exec rake test"
+script: "bundle exec rake test features"
diff --git a/Gemfile b/Gemfile
index c25f6833..8be637a1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ gemspec
 gem "cucumber", "~> 0.9.2"
 gem "rspec", "~>2.0.0"
 gem "rails", "~>3.0.0.rc"
-gem "compass-validator", "3.0.0"
+gem "compass-validator", "3.0.1"
 gem "css_parser", "~> 1.0.1"
 gem "sass", "~>3.1"
 gem "haml", "~> 3.1"
diff --git a/Gemfile.lock b/Gemfile.lock
index 9f979828..319f703a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,8 +7,8 @@ GIT
 PATH
   remote: .
   specs:
-    compass (0.11.1.f248c22)
-      chunky_png (~> 1.1)
+    compass (0.11.3.b352e8b)
+      chunky_png (~> 1.2)
       fssm (>= 0.2.7)
       sass (~> 3.1)
 
@@ -51,7 +51,7 @@ GEM
       sys-uname
     builder (2.1.2)
     chunky_png (1.2.0)
-    compass-validator (3.0.0)
+    compass-validator (3.0.1)
     css_parser (1.0.1)
     cucumber (0.9.4)
       builder (~> 2.1.2)
@@ -136,7 +136,7 @@ DEPENDENCIES
   autotest
   autotest-fsevent
   compass!
-  compass-validator (= 3.0.0)
+  compass-validator (= 3.0.1)
   css_parser (~> 1.0.1)
   cucumber (~> 0.9.2)
   diff-lcs (~> 1.1.2)
diff --git a/compass.gemspec b/compass.gemspec
index 87e2436f..d6c1194e 100644
--- a/compass.gemspec
+++ b/compass.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |gemspec|
   gemspec.summary = %q{A Real Stylesheet Framework}
 
   gemspec.add_dependency 'sass', '~> 3.1'
-  gemspec.add_dependency 'chunky_png', '~> 1.1'
+  gemspec.add_dependency 'chunky_png', '~> 1.2'
   gemspec.add_dependency 'fssm', '>= 0.2.7'
 
   gemspec.files = %w(README.markdown LICENSE.markdown VERSION.yml Rakefile)
diff --git a/doc-src/content/CHANGELOG.markdown b/doc-src/content/CHANGELOG.markdown
index a8c18baa..588b699b 100644
--- a/doc-src/content/CHANGELOG.markdown
+++ b/doc-src/content/CHANGELOG.markdown
@@ -14,6 +14,29 @@ The Documentation for the [latest stable release](http://compass-style.org/docs/
 
 The Documentation for the [latest preview release](http://beta.compass-style.org/)
 
+0.11.3 (06/11/2011)
+-------------------
+
+**Note:** Due to some internal changes to compass you may have issue with your sass cache. Run `compass clean` to clear your cache.
+
+* The `pie-clearfix` mixin has been updated. If you have to
+  support Firefox < 3.5, please update your stylesheets
+  to use `legacy-pie-clearfix` instead.
+* Added a new command: `compass clean` which removes any generated
+  css files and clears the sass cache.
+* Enable IE 10 support for flexible box with the -ms prefix.
+* A small change to how generated sprites are named for better
+  rails 3.1 compatibility.
+* Fixes for the compass --quiet mode.
+* It is now possible to generate cache buster urls that manipulate
+  the path of the image instead of the query string. This makes
+  images work better with proxies, but will require some web server
+  configuration. [Docs](/help/tutorials/configuration-reference/#asset-cache-buster)
+* Numerous small bug fixes to sprites.
+* Sprite Engines are now classes see [Docs](/help/tutorials/extending) for more information
+* Sprite classes have bee re-factored into modules for readability
+* Sprites will no longer cause `undefined method 'find' for #<Compass::SpriteMap>` when adding or removing sprite files
+
 0.11.2 (06/10/2011)
 -------------------
 * Sprites will now by default remove any old versions of the sprite. A new configuration
diff --git a/doc-src/content/help/tutorials/configuration-reference.markdown b/doc-src/content/help/tutorials/configuration-reference.markdown
index af6d6ea7..642707ca 100644
--- a/doc-src/content/help/tutorials/configuration-reference.markdown
+++ b/doc-src/content/help/tutorials/configuration-reference.markdown
@@ -307,10 +307,14 @@ the asset host configuration is ignored.
 
 ---
 
+<a name="asset-cache-buster"></a>
 **`asset_cache_buster`** – Pass this function a block of code that defines the
-cache buster strategy to be used. The block must return nil or a string that can
-be appended to a url as a query parameter. The returned string must not include
-the starting `?`. The block will be passed the root-relative url of the asset.
+cache buster strategy to be used. The block must return nil, a string or a hash.
+If the returned value is a hash the values of :path and/or :query is used to generate
+a cache busted path to the asset. If a string value is returned, it is added as a query string.
+The returned values for query strings must not include the starting `?`.
+
+The block will be passed the root-relative url of the asset.
 If the block accepts two arguments, it will also be passed a path
 that points to the asset on disk — which may or may not exist.
 
@@ -324,6 +328,18 @@ that points to the asset on disk — which may or may not exist.
       end
     end
 
+Busting the cache via path:
+
+    asset_cache_buster do |path, real_path|
+      if File.exists?(real_path)
+        pathname = Pathname.new(path)
+        modified_time = File.mtime(real_path).strftime("%s")
+        new_path = "%s/%s-%s%s" % [pathname.dirname, pathname.basename(pathname.extname), modified_time, pathname.extname]
+
+        {:path => new_path, :query => nil}
+      end
+    end
+
 To disable the asset cache buster:
 
     asset_cache_buster :none
diff --git a/doc-src/content/help/tutorials/extending.markdown b/doc-src/content/help/tutorials/extending.markdown
index 9d7f4d88..e07fe249 100644
--- a/doc-src/content/help/tutorials/extending.markdown
+++ b/doc-src/content/help/tutorials/extending.markdown
@@ -14,11 +14,9 @@ The sprite engine is the work horse of sprite generation it's the interface for
 
 ### Requirements
 
-A sprite engine requires only one method and that is `construct_sprite` which must return an object that responds to `save(filepath)`
+A sprite engine requires two methods `construct_sprite`, and `save(filename)`
 
-Once inside this method you have access to `images` which is a collection of [Compass::SassExtensions::Sprites::Image](http://rdoc.info/github/chriseppstein/compass/dda7c9/Compass/SassExtensions/Sprites/Image)
-
-Since the Engine module extends base you also have access to all methods in [Compass::SassExtensions::Sprites::Base](http://rdoc.info/github/chriseppstein/compass/dda7c9/Compass/SassExtensions/Sprites/Base)
+Once inside the class you have access to `images` which is a collection of [Compass::SassExtensions::Sprites::Image](http://rdoc.info/github/chriseppstein/compass/dda7c9/Compass/SassExtensions/Sprites/Image)
 
 ### Configuration 
 
@@ -26,7 +24,7 @@ To enable your sprite engine from the config file set
     
     sprite_engine = :<engine name>
 
-The example below will load `Compass::SassExtension::Sprites::ChunkyPngEngine`
+The example below will load `Compass::SassExtension::Sprites::ChunkyPngEngine.new(width, height, images)`
 
     sprite_engine = :chunky_png
 
@@ -35,13 +33,16 @@ The example below will load `Compass::SassExtension::Sprites::ChunkyPngEngine`
     module Compass
       module SassExtensions
         module Sprites
-          module <engine name>Engine
+          class ChunkyPngEngine < Compass::SassExtensions::Sprites::Engine
 
-            # Returns an object
             def construct_sprite
-              #must return a image object that responds to save(filename)
+              #do something
+            end    
+        
+            def save(filename)
+              #save file
             end
-
+        
           end
         end
       end
diff --git a/doc-src/content/help/tutorials/spriting.markdown b/doc-src/content/help/tutorials/spriting.markdown
index bf3d1b08..82874aef 100644
--- a/doc-src/content/help/tutorials/spriting.markdown
+++ b/doc-src/content/help/tutorials/spriting.markdown
@@ -34,7 +34,7 @@ And you'll get the following CSS output:
     .icon-delete,
     .icon-edit,
     .icon-new,
-    .icon-save   { background: url('/images/icon-34fe0604ab.png') no-repeat; }
+    .icon-save   { background: url('/images/icon-s34fe0604ab.png') no-repeat; }
     
     .icon-delete { background-position: 0 0; }
     .icon-edit   { background-position: 0 -32px; }
@@ -74,7 +74,7 @@ And your stylesheet will compile to:
     .actions .new,
     .actions .edit,
     .actions .save,
-    .actions .delete { background: url('/images/icon-34fe0604ab.png') no-repeat; }
+    .actions .delete { background: url('/images/icon-s34fe0604ab.png') no-repeat; }
     
     .actions .new    { background-position: 0 -64px; }
     .actions .edit   { background-position: 0 -32px; }
@@ -122,7 +122,7 @@ Now in our sass file we add:
 And your stylesheet will compile to:
 
     .selectors-sprite, a {
-      background: url('/selectors-edfef809e2.png') no-repeat;
+      background: url('/selectors-sedfef809e2.png') no-repeat;
     }
 
     a {
@@ -141,7 +141,7 @@ And your stylesheet will compile to:
 Alternatively you can use the `@include all-selectors-sprites;` after the import and get the following output:
 
     .selectors-sprite, .selectors-ten-by-ten {
-      background: url('/selectors-edfef809e2.png') no-repeat;
+      background: url('/selectors-sedfef809e2.png') no-repeat;
     }
 
     .selectors-ten-by-ten {
diff --git a/features/command_line.feature b/features/command_line.feature
index f0be79b1..06e0060c 100644
--- a/features/command_line.feature
+++ b/features/command_line.feature
@@ -145,6 +145,7 @@ Feature: Command Line
   Scenario: Basic help
     When I run: compass help
     Then I should see the following "primary" commands:
+      | clean   |
       | compile |
       | create  |
       | init    |
@@ -179,6 +180,27 @@ Feature: Command Line
     And I run: compass compile
     And a css file tmp/layout.css is reported overwritten
 
+  Scenario: Cleaning a project
+    Given I am using the existing project in test/fixtures/stylesheets/compass
+    When I run: compass compile
+    And I run: compass clean
+    Then the following files are reported removed:
+      | .sass-cache/                |
+      | tmp/border_radius.css       |
+      | tmp/box.css                 |
+      | tmp/box_shadow.css          |
+      | tmp/columns.css             |
+      | tmp/fonts.css               |
+      | images/flag-s03c3b29b35.png |
+    And the following files are removed:
+      | .sass-cache/                |
+      | tmp/border_radius.css       |
+      | tmp/box.css                 |
+      | tmp/box_shadow.css          |
+      | tmp/columns.css             |
+      | tmp/fonts.css               |
+      | images/flag-s03c3b29b35.png |
+
   Scenario: Watching a project for changes
     Given ruby supports fork
     Given I am using the existing project in test/fixtures/stylesheets/compass
@@ -218,7 +240,6 @@ Feature: Command Line
       | sass_dir | sass       |
       | css_dir  | assets/css |
 
-  @now
   Scenario Outline: Print out a configuration value
     Given I am using the existing project in test/fixtures/stylesheets/compass
     When I run: compass config -p <property>
diff --git a/features/step_definitions/command_line_steps.rb b/features/step_definitions/command_line_steps.rb
index 0b4407fa..5bddd7a7 100644
--- a/features/step_definitions/command_line_steps.rb
+++ b/features/step_definitions/command_line_steps.rb
@@ -76,7 +76,7 @@ When /^I run in a separate process: compass ([^\s]+) ?(.+)?$/ do |command, args|
         file.puts $stdout.string
       end
       open('/tmp/last_error.compass_test.txt', 'w') do |file|
-        file.puts @stderr.string
+        file.puts $stderr.string
       end
       exit!
     end
@@ -116,10 +116,30 @@ Then /^a directory ([^ ]+) is (not )?created$/ do |directory, negated|
   File.directory?(directory).should == !negated
 end
  
+Then /an? \w+ file ([^ ]+) is (not )?removed/ do |filename, negated|
+  File.exists?(filename).should == !!negated
+end
+
 Then /an? \w+ file ([^ ]+) is (not )?created/ do |filename, negated|
   File.exists?(filename).should == !negated
 end
 
+Then "the following files are reported removed:" do |table|
+  table.rows.each do |css_file|
+    Then %Q{a css file #{css_file.first} is reported removed}
+  end
+end
+
+Then "the following files are removed:" do |table|
+  table.rows.each do |css_file|
+    Then %Q{a css file #{css_file.first} is removed}
+  end
+end
+
+Then /an? \w+ file ([^ ]+) is reported removed/ do |filename|
+  @last_result.should =~ /remove.*#{Regexp.escape(filename)}/
+end
+
 Then /an? \w+ file ([^ ]+) is reported created/ do |filename|
   @last_result.should =~ /create.*#{Regexp.escape(filename)}/
 end
diff --git a/frameworks/compass/stylesheets/compass/utilities/general/_clearfix.scss b/frameworks/compass/stylesheets/compass/utilities/general/_clearfix.scss
index 2c097cc1..73f9254c 100644
--- a/frameworks/compass/stylesheets/compass/utilities/general/_clearfix.scss
+++ b/frameworks/compass/stylesheets/compass/utilities/general/_clearfix.scss
@@ -18,7 +18,7 @@
 // [Easy Clearing](http://www.positioniseverything.net/easyclearing.html)
 // has the advantage of allowing positioned elements to hang
 // outside the bounds of the container at the expense of more tricky CSS.
-@mixin pie-clearfix {
+@mixin legacy-pie-clearfix {
   &:after {
     content    : "\0020";
     display    : block;
@@ -29,3 +29,16 @@
   }
   @include has-layout;
 }
+
+// This is an updated version of the PIE clearfix method that reduces the amount of CSS output.
+// If you need to support Firefox before 3.5 you need to use `legacy-pie-clearfix` instead.
+//
+// Adapted from: [A new micro clearfix hack](http://nicolasgallagher.com/micro-clearfix-hack/)
+@mixin pie-clearfix {
+  &:after {
+    content: "";
+    display: table;
+    clear: both;
+  }
+  @include has-layout;
+}
diff --git a/lib/compass/actions.rb b/lib/compass/actions.rb
index bc4a2b82..4e924f1b 100644
--- a/lib/compass/actions.rb
+++ b/lib/compass/actions.rb
@@ -65,7 +65,10 @@ module Compass
     end
 
     def remove(file_name)
-      if File.exists?(file_name)
+      if File.directory?(file_name)
+        FileUtils.rm_rf file_name
+        log_action :remove, basename(file_name)+"/", options
+      elsif File.exists?(file_name)
         File.unlink file_name
         log_action :remove, basename(file_name), options
       end
diff --git a/lib/compass/commands.rb b/lib/compass/commands.rb
index f4230ef4..42ca37ab 100644
--- a/lib/compass/commands.rb
+++ b/lib/compass/commands.rb
@@ -4,7 +4,7 @@ end
 require 'compass/commands/registry'
 
 %w(base generate_grid_background default help list_frameworks project_base
-   update_project watch_project create_project imports installer_command
+   update_project watch_project create_project clean_project imports installer_command
    print_version project_stats stamp_pattern sprite validate_project
    write_configuration interactive unpack_extension).each do |lib|
   require "compass/commands/#{lib}"
diff --git a/lib/compass/commands/clean_project.rb b/lib/compass/commands/clean_project.rb
new file mode 100644
index 00000000..e6792326
--- /dev/null
+++ b/lib/compass/commands/clean_project.rb
@@ -0,0 +1,79 @@
+require 'compass/commands/project_base'
+require 'compass/compiler'
+
+module Compass
+  module Commands
+    module CleanProjectOptionsParser
+      def set_options(opts)
+        opts.banner = %Q{
+          Usage: compass clean [path/to/project] [options]
+
+          Description:
+          Remove generated files and the sass cache.
+
+          Options:
+        }.split("\n").map{|l| l.gsub(/^ */,'')}.join("\n")
+
+        super
+      end
+    end
+
+    class CleanProject < UpdateProject
+
+      register :clean
+
+      def initialize(working_path, options)
+        super
+        assert_project_directory_exists!
+      end
+
+      def perform
+        compiler = new_compiler_instance
+        compiler.clean!
+        Compass::SpriteImporter.find_all_sprite_map_files(Compass.configuration.images_path).each do |sprite|
+          remove sprite
+        end
+      end
+
+      def determine_cache_location
+        Compass.configuration.cache_path || Sass::Plugin.options[:cache_location] || File.join(working_path, ".sass-cache")
+      end
+
+      class << self
+        def option_parser(arguments)
+          parser = Compass::Exec::CommandOptionParser.new(arguments)
+          parser.extend(Compass::Exec::GlobalOptionsParser)
+          parser.extend(Compass::Exec::ProjectOptionsParser)
+          parser.extend(CleanProjectOptionsParser)
+        end
+
+        def usage
+          option_parser([]).to_s
+        end
+
+        def primary; true; end
+
+        def description(command)
+          "Remove generated files and the sass cache"
+        end
+
+        def parse!(arguments)
+          parser = option_parser(arguments)
+          parser.parse!
+          parse_arguments!(parser, arguments)
+          parser.options
+        end
+
+        def parse_arguments!(parser, arguments)
+          if arguments.size > 0
+            parser.options[:project_name] = arguments.shift if File.directory?(arguments.first)
+            unless arguments.empty?
+              parser.options[:sass_files] = arguments.dup
+              parser.options[:force] = true
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/compass/commands/registry.rb b/lib/compass/commands/registry.rb
index 64372079..3b5c0d16 100644
--- a/lib/compass/commands/registry.rb
+++ b/lib/compass/commands/registry.rb
@@ -16,8 +16,10 @@ module Compass::Commands
         matching.first
       elsif name =~ /^-/
         nil
-      else
+      elsif matching.size > 1
         raise Compass::Error, "Ambiguous abbreviation '#{name}'. Did you mean one of: #{matching.join(", ")}"
+      else
+        raise Compass::Error, "Command not found: #{name}"
       end
     end
     def abbreviation?(name)
diff --git a/lib/compass/commands/sprite.rb b/lib/compass/commands/sprite.rb
index b1c8bee9..b93705ed 100644
--- a/lib/compass/commands/sprite.rb
+++ b/lib/compass/commands/sprite.rb
@@ -39,7 +39,7 @@ module Compass
 
       def perform
         relative_uri = options[:uri].gsub(/^#{Compass.configuration.images_dir}\//, '')
-        sprites = Compass::SpriteImporter.new(relative_uri, Compass.sass_engine_options)
+        sprites = Compass::SpriteImporter.new(:uri => relative_uri, :options => Compass.sass_engine_options)
         options[:output_file] ||= File.join(Compass.configuration.sass_path, "sprites", "_#{sprites.name}.#{Compass.configuration.preferred_syntax}")
         options[:skip_overrides] ||= false
         contents = sprites.content_for_images(options[:skip_overrides])
diff --git a/lib/compass/commands/update_project.rb b/lib/compass/commands/update_project.rb
index 1eb0a595..30e2654f 100644
--- a/lib/compass/commands/update_project.rb
+++ b/lib/compass/commands/update_project.rb
@@ -51,12 +51,10 @@ module Compass
 
       def new_compiler_instance(additional_options = {})
         @compiler_opts ||= begin
-          compiler_opts = Compass.sass_engine_options
-          compiler_opts.merge!(:force => options[:force],
-                               :sass_files => explicit_sass_files,
-                               :dry_run => options[:dry_run])
-          compiler_opts[:quiet] = options[:quiet] if options[:quiet]
-          compiler_opts[:time] = options[:time] if options[:time]
+          compiler_opts = {:sass => Compass.sass_engine_options}
+          compiler_opts.merge!(options)
+          compiler_opts[:sass_files] = explicit_sass_files
+          compiler_opts[:cache_location] = determine_cache_location
           compiler_opts
         end
 
diff --git a/lib/compass/compiler.rb b/lib/compass/compiler.rb
index e7f6feef..fe00ef66 100644
--- a/lib/compass/compiler.rb
+++ b/lib/compass/compiler.rb
@@ -3,16 +3,19 @@ module Compass
 
     include Actions
 
-    attr_accessor :working_path, :from, :to, :options, :staleness_checker, :importer
+    attr_accessor :working_path, :from, :to, :options, :sass_options, :staleness_checker, :importer
 
     def initialize(working_path, from, to, options)
       self.working_path = working_path
       self.from, self.to = from.gsub('./', ''), to
       self.logger = options.delete(:logger)
+      sass_opts = options.delete(:sass) || {}
       self.options = options
-      self.options[:cache_location] ||= determine_cache_location
-      options[:importer] = self.importer = Sass::Importers::Filesystem.new(from)
-      self.staleness_checker = Sass::Plugin::StalenessChecker.new(options)
+      self.sass_options = options.dup
+      self.sass_options.update(sass_opts)
+      self.sass_options[:cache_location] ||= determine_cache_location
+      self.sass_options[:importer] = self.importer = Sass::Importers::Filesystem.new(from)
+      self.staleness_checker = Sass::Plugin::StalenessChecker.new(sass_options)
     end
 
     def determine_cache_location
@@ -72,16 +75,16 @@ module Compass
     end
 
     def clean!
-      FileUtils.rm_rf options[:cache_location]
+      remove options[:cache_location]
       css_files.each do |css_file|
-        FileUtils.rm_f css_file
+        remove css_file
       end
     end
 
     def run
       if new_config?
         # Wipe out the cache and force compilation if the configuration has changed.
-        FileUtils.rm_rf options[:cache_location]
+        remove options[:cache_location]
         options[:force] = true
       end
 
@@ -142,7 +145,7 @@ module Compass
     # A sass engine for compiling a single file.
     def engine(sass_filename, css_filename)
       syntax = (sass_filename =~ /\.(s[ac]ss)$/) && $1.to_sym || :sass
-      opts = options.merge :filename => sass_filename, :css_filename => css_filename, :syntax => syntax
+      opts = sass_options.merge(:filename => sass_filename, :css_filename => css_filename, :syntax => syntax)
       Sass::Engine.new(open(sass_filename).read, opts)
     end
 
diff --git a/lib/compass/configuration/data.rb b/lib/compass/configuration/data.rb
index 9cde724d..ddc2de3a 100644
--- a/lib/compass/configuration/data.rb
+++ b/lib/compass/configuration/data.rb
@@ -71,8 +71,10 @@ module Compass
       end
 
       # When called with a block, defines the cache buster strategy to be used.
-      # The block must return nil or a string that can be appended to a url as a query parameter.
-      # The returned string must not include the starting '?'.
+      # If the block returns nil or a string, then it is appended to the url as a query parameter.
+      # In this case, the returned string must not include the starting '?'.
+      # The block may also return a hash with :path and/or :query values and it
+      # will replace the original path and query string with the busted values returned.
       # The block will be passed the root-relative url of the asset.
       # If the block accepts two arguments, it will also be passed a File object
       # that points to the asset on disk -- which may or may not exist.
diff --git a/lib/compass/exec/sub_command_ui.rb b/lib/compass/exec/sub_command_ui.rb
index 972f82c8..43a5a308 100644
--- a/lib/compass/exec/sub_command_ui.rb
+++ b/lib/compass/exec/sub_command_ui.rb
@@ -13,6 +13,7 @@ module Compass::Exec
     def run!
       begin
         perform!
+        return 0
       rescue Exception => e
         raise e if e.is_a? SystemExit
         if e.is_a?(::Compass::Error) || e.is_a?(OptionParser::ParseError)
@@ -22,7 +23,6 @@ module Compass::Exec
         end
         return 1
       end
-      return 0
     end
     
     protected
diff --git a/lib/compass/sass_extensions/functions/urls.rb b/lib/compass/sass_extensions/functions/urls.rb
index d140c8a5..50ffab52 100644
--- a/lib/compass/sass_extensions/functions/urls.rb
+++ b/lib/compass/sass_extensions/functions/urls.rb
@@ -91,9 +91,7 @@ module Compass::SassExtensions::Functions::Urls
       if cache_buster.is_a?(Sass::Script::String)
         path += "?#{cache_buster.value}"
       else
-        if buster = compute_cache_buster(path, real_path)
-          path += "?#{buster}"
-        end
+        path = cache_busted_path(path, real_path)
       end
     end
 
@@ -137,6 +135,23 @@ module Compass::SassExtensions::Functions::Urls
     end
   end
 
+  def cache_busted_path(path, real_path)
+    cache_buster = compute_cache_buster(path, real_path)
+    if cache_buster.nil?
+      return path
+    elsif cache_buster.is_a?(String)
+      cache_buster = {:query => cache_buster}
+    else
+      path = cache_buster[:path] if cache_buster[:path]
+    end
+    
+    if cache_buster[:query]
+      "%s?%s" % [path, cache_buster[:query]]
+    else
+      path
+    end
+  end
+
   def compute_cache_buster(path, real_path)
     if Compass.configuration.asset_cache_buster
       args = [path]
diff --git a/lib/compass/sass_extensions/sprites.rb b/lib/compass/sass_extensions/sprites.rb
index d22ab96b..ab35d84e 100644
--- a/lib/compass/sass_extensions/sprites.rb
+++ b/lib/compass/sass_extensions/sprites.rb
@@ -9,6 +9,8 @@ module Compass
 end
 
 require 'compass/sass_extensions/sprites/image'
+require 'compass/sass_extensions/sprites/sprite_methods'
+require 'compass/sass_extensions/sprites/image_methods'
 require 'compass/sass_extensions/sprites/sprite_map'
 require 'compass/sass_extensions/sprites/engines'
 
diff --git a/lib/compass/sass_extensions/sprites/engines.rb b/lib/compass/sass_extensions/sprites/engines.rb
index 26a73260..0fa6d1b5 100644
--- a/lib/compass/sass_extensions/sprites/engines.rb
+++ b/lib/compass/sass_extensions/sprites/engines.rb
@@ -1 +1,25 @@
+module Compass
+  module SassExtensions
+    module Sprites
+      class Engine
+        attr_accessor :width, :height, :images, :canvas
+        def initialize(width, height, images)
+          @width, @height, @images = width, height, images
+          @canvas = nil
+        end
+        
+        def construct_sprite
+          raise ::Compass::Error, "You must impliment construct_sprite"
+        end
+        
+        def save(filename)
+          raise ::Compass::Error, "You must impliment save(filename)"
+        end
+        
+      end
+    end
+  end
+end
+
+
 require 'compass/sass_extensions/sprites/engines/chunky_png_engine'
\ No newline at end of file
diff --git a/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb b/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb
index dd7a6455..c26caa11 100644
--- a/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb
+++ b/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb
@@ -7,20 +7,19 @@ end
 module Compass
   module SassExtensions
     module Sprites
-      module ChunkyPngEngine
-        
-        # Returns a PNG object
+      class ChunkyPngEngine < Compass::SassExtensions::Sprites::Engine
+
         def construct_sprite
-          output_png = ChunkyPNG::Image.new(width, height, ChunkyPNG::Color::TRANSPARENT)
+          @canvas = ChunkyPNG::Image.new(width, height, ChunkyPNG::Color::TRANSPARENT)
           images.each do |image|
             input_png  = ChunkyPNG::Image.from_file(image.file)
             if image.repeat == "no-repeat"
-              output_png.replace! input_png, image.left, image.top
+              canvas.replace! input_png, image.left, image.top
             else
               x = image.left - (image.left / image.width).ceil * image.width
               while x < width do
                 begin
-                  output_png.replace! input_png, x, image.top
+                  canvas.replace! input_png, x, image.top
                   x += image.width 
                 rescue ChunkyPNG::OutOfBounds
                   break;
@@ -28,8 +27,15 @@ module Compass
               end
             end
           end
-          output_png
+        end    
+        
+        def save(filename)
+          if canvas.nil?
+            construct_sprite
+          end
+          canvas.save(filename, :best_compression)
         end
+        
       end
     end
   end
diff --git a/lib/compass/sass_extensions/sprites/image_methods.rb b/lib/compass/sass_extensions/sprites/image_methods.rb
new file mode 100644
index 00000000..f492d59f
--- /dev/null
+++ b/lib/compass/sass_extensions/sprites/image_methods.rb
@@ -0,0 +1,32 @@
+module Compass
+  module SassExtensions
+    module Sprites
+      module ImageMethods
+        # Fetches the Sprite::Image object for the supplied name
+         def image_for(name)
+           @images.detect { |img| img.name == name}
+         end
+
+         # Returns true if the image name has a hover selector image
+         def has_hover?(name)
+           !image_for("#{name}_hover").nil?
+         end
+
+         # Returns true if the image name has a target selector image
+         def has_target?(name)
+           !image_for("#{name}_target").nil?
+         end
+
+         # Returns true if the image name has an active selector image
+         def has_active?(name)
+           !image_for("#{name}_active").nil?
+         end
+
+         # Return and array of image names that make up this sprite
+         def sprite_names
+           image_names.map { |f| File.basename(f, '.png') }
+         end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/compass/sass_extensions/sprites/sprite_map.rb b/lib/compass/sass_extensions/sprites/sprite_map.rb
index bf1e813d..546dd1d1 100644
--- a/lib/compass/sass_extensions/sprites/sprite_map.rb
+++ b/lib/compass/sass_extensions/sprites/sprite_map.rb
@@ -2,8 +2,13 @@ module Compass
   module SassExtensions
     module Sprites
       class SpriteMap < Sass::Script::Literal
-        
-        
+        attr_accessor :image_names, :path, :name, :map, :kwargs
+        attr_accessor :images, :width, :height, :engine
+
+        include SpriteMethods
+        include ImageMethods
+
+
         # Initialize a new sprite object from a relative file path
         # the path is relative to the <tt>images_path</tt> confguration option
         def self.from_uri(uri, context, kwargs)
@@ -13,22 +18,8 @@ module Compass
           end
           new(sprites, importer.path, importer.name, context, kwargs)
         end
-        
-        # Loads the sprite engine
-        def require_engine!
-          self.class.send(:include, eval("::Compass::SassExtensions::Sprites::#{modulize}Engine"))
-        end
-      
-        # Changing this string will invalidate all previously generated sprite images.
-        # We should do so only when the packing algorithm changes
-        SPRITE_VERSION = "1"
-
-        attr_accessor :image_names, :path, :name, :kwargs
-        attr_accessor :images, :width, :height
-
 
         def initialize(sprites, path, name, context, kwargs)
-          require_engine!
           @image_names = sprites
           @path = path
           @name = name
@@ -37,150 +28,12 @@ module Compass
           @images = nil
           @width = nil
           @height = nil
+          @engine = nil
           @evaluation_context = context
           validate!
           compute_image_metadata!
         end
 
-        # Calculate the size of the sprite
-        def size
-          [width, height]
-        end
-      
-        # Calculates the overal image dimensions
-        # collects image sizes and input parameters for each sprite
-        # Calculates the height
-        def compute_image_metadata!
-          @width = 0
-          init_images
-          compute_image_positions!
-          @height = @images.last.top + @images.last.height
-        end
-        
-        # Creates the Sprite::Image objects for each image and calculates the width
-        def init_images
-          @images = image_names.collect do |relative_file|
-            image = Compass::SassExtensions::Sprites::Image.new(self, relative_file, kwargs)
-            @width = [ @width, image.width + image.offset ].max
-            image
-          end
-        end
-        
-        # Calculates the overal image dimensions
-        # collects image sizes and input parameters for each sprite
-        def compute_image_positions!
-          @images.each_with_index do |image, index|
-            image.left = image.position.unit_str == "%" ? (@width - image.width) * (image.position.value / 100) : image.position.value
-            next if index == 0
-            last_image = @images[index-1]
-            image.top = last_image.top + last_image.height + [image.spacing,  last_image.spacing].max
-          end
-        end
-        
-        # Fetches the Sprite::Image object for the supplied name
-        def image_for(name)
-          @images.detect { |img| img.name == name}
-        end
-        
-        # Returns true if the image name has a hover selector image
-        def has_hover?(name)
-          !image_for("#{name}_hover").nil?
-        end
-        
-        # Returns true if the image name has a target selector image
-        def has_target?(name)
-          !image_for("#{name}_target").nil?
-        end
-        
-        # Returns true if the image name has an active selector image
-        def has_active?(name)
-          !image_for("#{name}_active").nil?
-        end
-        
-        # Return and array of image names that make up this sprite
-        def sprite_names
-          image_names.map { |f| File.basename(f, '.png') }
-        end
-
-
-        # Validates that the sprite_names are valid sass
-        def validate!
-          for sprite_name in sprite_names
-            unless sprite_name =~ /\A#{Sass::SCSS::RX::IDENT}\Z/
-              raise Sass::SyntaxError, "#{sprite_name} must be a legal css identifier"
-            end
-          end
-        end
-
-        # The on-the-disk filename of the sprite
-        def filename
-          File.join(Compass.configuration.images_path, "#{path}-s#{uniqueness_hash}.png")
-        end
-
-        # Generate a sprite image if necessary
-        def generate
-          if generation_required?
-            if kwargs.get_var('cleanup').value
-              cleanup_old_sprites
-            end
-            sprite_data = construct_sprite
-            save!(sprite_data)
-            Compass.configuration.run_callback(:sprite_generated, sprite_data)
-          end
-        end
-        
-        def cleanup_old_sprites
-          Dir[File.join(Compass.configuration.images_path, "#{path}-*.png")].each do |file|
-            FileUtils.rm file
-          end
-        end
-        
-        # Does this sprite need to be generated
-        def generation_required?
-          !File.exists?(filename) || outdated?
-        end
-
-        # Returns the uniqueness hash for this sprite object
-        def uniqueness_hash
-          @uniqueness_hash ||= begin
-            sum = Digest::MD5.new
-            sum << SPRITE_VERSION
-            sum << path
-            images.each do |image|
-              [:relative_file, :height, :width, :repeat, :spacing, :position, :digest].each do |attr|
-                sum << image.send(attr).to_s
-              end
-            end
-            sum.hexdigest[0...10]
-          end
-          @uniqueness_hash
-        end
-
-        # Saves the sprite engine
-        def save!(output_png)
-          saved = output_png.save filename
-          Compass.configuration.run_callback(:sprite_saved, filename)
-          saved
-        end
-
-        # All the full-path filenames involved in this sprite
-        def image_filenames
-          @images.map(&:file)
-        end
-
-        # Checks whether this sprite is outdated
-        def outdated?
-          if File.exists?(filename)
-            return @images.map(&:mtime).any? { |imtime| imtime.to_i > self.mtime.to_i }
-          end
-          true
-        end
-
-        # Mtime of the sprite file
-        def mtime
-          @mtime ||= File.mtime(filename)
-        end
-
         def inspect
           to_s
         end
@@ -200,14 +53,14 @@ module Compass
             super
           end
         end
-        
+
         private 
-        
+
         def modulize
           @modulize ||= Compass::configuration.sprite_engine.to_s.scan(/([^_.]+)/).flatten.map {|chunk| "#{chunk[0].chr.upcase}#{chunk[1..-1]}" }.join
         end
-        
+
       end
     end
   end
-end
+end
\ No newline at end of file
diff --git a/lib/compass/sass_extensions/sprites/sprite_methods.rb b/lib/compass/sass_extensions/sprites/sprite_methods.rb
new file mode 100644
index 00000000..c620e95a
--- /dev/null
+++ b/lib/compass/sass_extensions/sprites/sprite_methods.rb
@@ -0,0 +1,134 @@
+module Compass
+  module SassExtensions
+    module Sprites
+      module SpriteMethods
+        
+        # Changing this string will invalidate all previously generated sprite images.
+        # We should do so only when the packing algorithm changes
+        SPRITE_VERSION = "1"
+        
+        # Calculates the overal image dimensions
+        # collects image sizes and input parameters for each sprite
+        # Calculates the height
+        def compute_image_metadata!
+          @width = 0
+          init_images
+          compute_image_positions!
+          @height = @images.last.top + @images.last.height
+          init_engine
+        end
+        
+        def init_engine
+          @engine = eval("::Compass::SassExtensions::Sprites::#{modulize}Engine.new(nil, nil, nil)")
+          @engine.width = @width
+          @engine.height = @height
+          @engine.images = @images
+        end
+        
+        # Creates the Sprite::Image objects for each image and calculates the width
+        def init_images
+          @images = image_names.collect do |relative_file|
+            image = Compass::SassExtensions::Sprites::Image.new(self, relative_file, kwargs)
+            @width = [ @width, image.width + image.offset ].max
+            image
+          end
+        end
+        
+        # Calculates the overal image dimensions
+        # collects image sizes and input parameters for each sprite
+        def compute_image_positions!
+          @images.each_with_index do |image, index|
+            image.left = image.position.unit_str == "%" ? (@width - image.width) * (image.position.value / 100) : image.position.value
+            next if index == 0
+            last_image = @images[index-1]
+            image.top = last_image.top + last_image.height + [image.spacing,  last_image.spacing].max
+          end
+        end
+        
+        # Validates that the sprite_names are valid sass
+        def validate!
+          for sprite_name in sprite_names
+            unless sprite_name =~ /\A#{Sass::SCSS::RX::IDENT}\Z/
+              raise Sass::SyntaxError, "#{sprite_name} must be a legal css identifier"
+            end
+          end
+        end
+
+        # The on-the-disk filename of the sprite
+        def filename
+          File.join(Compass.configuration.images_path, "#{path}-s#{uniqueness_hash}.png")
+        end
+
+        # Generate a sprite image if necessary
+        def generate
+          if generation_required?
+            if kwargs.get_var('cleanup').value
+              cleanup_old_sprites
+            end
+            engine.construct_sprite
+            Compass.configuration.run_callback(:sprite_generated, engine.canvas)
+            save!
+          end
+        end
+        
+        def cleanup_old_sprites
+          Dir[File.join(Compass.configuration.images_path, "#{path}-*.png")].each do |file|
+            FileUtils.rm file
+          end
+        end
+        
+        # Does this sprite need to be generated
+        def generation_required?
+          !File.exists?(filename) || outdated?
+        end
+
+        # Returns the uniqueness hash for this sprite object
+        def uniqueness_hash
+          @uniqueness_hash ||= begin
+            sum = Digest::MD5.new
+            sum << SPRITE_VERSION
+            sum << path
+            images.each do |image|
+              [:relative_file, :height, :width, :repeat, :spacing, :position, :digest].each do |attr|
+                sum << image.send(attr).to_s
+              end
+            end
+            sum.hexdigest[0...10]
+          end
+          @uniqueness_hash
+        end
+
+        # Saves the sprite engine
+        def save!
+          saved = engine.save(filename)
+          Compass.configuration.run_callback(:sprite_saved, filename)
+          saved
+        end
+
+        # All the full-path filenames involved in this sprite
+        def image_filenames
+          @images.map(&:file)
+        end
+
+        # Checks whether this sprite is outdated
+        def outdated?
+          if File.exists?(filename)
+            return @images.map(&:mtime).any? { |imtime| imtime.to_i > self.mtime.to_i }
+          end
+          true
+        end
+
+        # Mtime of the sprite file
+        def mtime
+          @mtime ||= File.mtime(filename)
+        end
+        
+       # Calculate the size of the sprite
+        def size
+          [width, height]
+        end
+
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/compass/sprite_importer.rb b/lib/compass/sprite_importer.rb
index 94d3b11e..3dd1bd3e 100644
--- a/lib/compass/sprite_importer.rb
+++ b/lib/compass/sprite_importer.rb
@@ -4,7 +4,14 @@ module Compass
     VAILD_FILE_NAME = /\A#{Sass::SCSS::RX::IDENT}\Z/
     SPRITE_IMPORTER_REGEX = %r{((.+/)?([^\*.]+))/(.+?)\.png}
     VALID_EXTENSIONS = ['.png']
-    
+
+    # finds all sprite files
+    def self.find_all_sprite_map_files(path)
+      hex = "[0-9a-f]"
+      glob = "*-{,s}#{hex*10}{#{VALID_EXTENSIONS.join(",")}}"
+      Dir.glob(File.join(path, "**", glob))
+    end
+
     def self.load(uri, options)
       klass = Compass::SpriteImporter.new
       klass.uri, klass.options = uri, options
@@ -31,7 +38,7 @@ module Compass
     end
     
     def to_s
-      content_for_images
+      self.class.name
     end
     
     def hash
diff --git a/lib/compass/validator.rb b/lib/compass/validator.rb
index adb9b9d8..f8197a3f 100644
--- a/lib/compass/validator.rb
+++ b/lib/compass/validator.rb
@@ -1,9 +1,16 @@
 begin
   require 'rubygems'
   require 'compass-validator'
-rescue LoadError
-  raise Compass::MissingDependency, %Q{The Compass CSS Validator could not be loaded. Please install it:
-
+rescue LoadError => e
+  if e.message =~ /core_ext/
+    raise Compass::MissingDependency, <<-ERRORMSG
+The Compass CSS Validator is out of date. Please upgrade it:
+sudo gem install compass-validator --version ">= 3.0.1"
+ERRORMSG
+  else
+    raise Compass::MissingDependency, <<-ERRORMSG
+The Compass CSS Validator could not be loaded. Please install it:
 sudo gem install compass-validator
-}
+ERRORMSG
+  end
 end
diff --git a/spec/compass/sass_extensions/sprites/base_spec.rb b/spec/compass/sass_extensions/sprites/base_spec.rb
deleted file mode 100644
index 4769e172..00000000
--- a/spec/compass/sass_extensions/sprites/base_spec.rb
+++ /dev/null
@@ -1,57 +0,0 @@
-require 'spec_helper'
-describe Compass::SassExtensions::Sprites::Base do
-  
-  before :each do
-    @images_src_path = File.join(File.dirname(__FILE__), '..', '..', '..', 'test_project', 'public', 'images')
-    @images_tmp_path = File.join(File.dirname(__FILE__), '..', '..', '..', 'test_project', 'public', 'images-tmp')
-    FileUtils.cp_r @images_src_path, @images_tmp_path
-    config = Compass::Configuration::Data.new('config')
-    config.images_path = @images_tmp_path
-    Compass.add_configuration(config)
-    Compass.configure_sass_plugin!
-    #fix this eww
-    options = Compass.sass_engine_options.extend Compass::SassExtensions::Functions::Sprites::VariableReader
-    @map = Compass::SpriteImporter.new("selectors/*.png", options)
-    @base = Compass::SassExtensions::Sprites::Base.new(@map.sprite_names.map{|n| "selectors/#{n}.png"}, @map.path, 'selectors', @map.sass_engine, @map.options)
-  end
-
-  after :each do
-    FileUtils.rm_r @images_tmp_path
-  end
-  
-  subject { @base }
-  
-  its(:size) { should == [10,40] }
-  its(:sprite_names) { should ==  @map.sprite_names }
-  its(:image_filenames) { should == Dir["#{@images_tmp_path}/selectors/*.png"].sort }
-  its(:generation_required?) { should be_true }
-  its(:uniqueness_hash) { should == 'ef52c5c63a'}
-  its(:outdated?) { should be_true }
-  its(:filename) { should == File.join(@images_tmp_path, "#{@base.path}-s#{@base.uniqueness_hash}.png")}
-  
-  it "should return the 'ten-by-ten' image" do
-    subject.image_for('ten-by-ten').name.should == 'ten-by-ten'
-    subject.image_for('ten-by-ten').should be_a Compass::SassExtensions::Sprites::Image
-  end
-  
-  %w(target hover active).each do |selector|
-    it "should have a #{selector}" do
-      subject.send(:"has_#{selector}?", 'ten-by-ten').should be_true
-    end
-    
-    it "should return #{selector} image class" do
-      subject.image_for('ten-by-ten').send(:"#{selector}").name.should == "ten-by-ten_#{selector}"
-    end
-    
-  end
-  context "#generate" do
-    before { @base.generate }
-    it "should generate sprite" do
-      File.exists?(@base.filename).should be_true
-    end
-    
-    its(:generation_required?) { should be_false }
-    its(:outdated?) { should be_false }
-  end
-  
-end
\ No newline at end of file
diff --git a/spec/compass/sass_extensions/sprites/image_spec.rb b/spec/compass/sass_extensions/sprites/image_spec.rb
deleted file mode 100644
index f328a535..00000000
--- a/spec/compass/sass_extensions/sprites/image_spec.rb
+++ /dev/null
@@ -1,161 +0,0 @@
-require 'spec_helper'
-require 'compass/sass_extensions/sprites/image'
-
-describe Compass::SassExtensions::Sprites::Image do
-  let(:sprite_filename) { 'squares/ten-by-ten.png' }
-  let(:sprite_path) { File.join(images_src_path, sprite_filename) }
-  let(:sprite_name) { File.basename(sprite_filename, '.png') }
-  let(:parent) do
-    mock
-  end
-  before do
-    parent.stubs(:image_for).with('ten-by-ten').returns(image)
-    parent.stubs(:image_for).with('ten-by-ten_hover').returns(hover_image)
-  end
-  let(:image) { self.class.describes.new(parent, File.join(sprite_filename), options)}
-  let(:hover_image) { self.class.describes.new(parent, File.join('selectors/ten-by-ten_hover.png'), options)}
-  let(:digest) { Digest::MD5.file(sprite_path).hexdigest }
-  subject { image }
-
-  before {
-    file = StringIO.new("images_path = #{images_src_path.inspect}\n")
-    Compass.add_configuration(file, "sprite_config")
-  }
-
-  describe '#initialize' do
-    its(:name) { should == sprite_name }
-    its(:file) { should == sprite_path }
-    its(:relative_file) { should == sprite_filename }
-    its(:width) { should == 10 }
-    its(:height) { should == 10 }
-    its(:digest) { should == digest }
-    its(:top) { should == 0 }
-    its(:left) { should == 0 }
-  end
-
-  let(:get_var_expects) { nil }
-  let(:get_var_return) { nil }
-
-  let(:options) {
-    options = mock
-    options.stubs(:get_var).with(anything).returns(nil)
-    options.stubs(:get_var).with(get_var_expects).returns(get_var_return)
-    options
-  }
-  
-  describe '#parent' do
-    context '_hover' do
-      subject { hover_image }
-      its(:parent) { should == image }
-    end
-    context 'no parent' do
-      subject { image }
-      its(:parent) { should be_nil }
-    end
-  end
-  
-  describe '#repeat' do
-    let(:type) { nil }
-    let(:get_var_return) { OpenStruct.new(:value => type) }
-
-    context 'specific image' do
-      let(:type) { 'specific' }
-      let(:get_var_expects) { "#{sprite_name}-repeat" }
-
-      its(:repeat) { should == type }
-    end
-
-    context 'global' do
-      let(:type) { 'global' }
-      let(:get_var_expects) { 'repeat' }
-
-      its(:repeat) { should == type }
-    end
-
-    context 'default' do
-      let(:get_var_expects) { nil }
-
-      its(:repeat) { should == "no-repeat" }
-    end
-  end
-
-  describe '#position' do
-    let(:type) { nil }
-    let(:get_var_return) { type }
-
-    context 'specific image' do
-      let(:type) { 'specific' }
-      let(:get_var_expects) { "#{sprite_name}-position" }
-
-      its(:position) { should == type }
-    end
-
-    context 'global' do
-      let(:type) { 'global' }
-      let(:get_var_expects) { 'position' }
-
-      its(:position) { should == type }
-    end
-
-    context 'default' do
-      let(:get_var_expects) { nil }
-
-      its(:position) { should == Sass::Script::Number.new(0, ["px"]) }
-    end
-  end
-
-  describe '#spacing' do
-    let(:type) { nil }
-    let(:get_var_return) { OpenStruct.new(:value => type) }
-
-    context 'specific image' do
-      let(:type) { 'specific' }
-      let(:get_var_expects) { "#{sprite_name}-spacing" }
-
-      its(:spacing) { should == type }
-    end
-
-    context 'global' do
-      let(:type) { 'global' }
-      let(:get_var_expects) { 'spacing' }
-
-      its(:spacing) { should == type }
-    end
-
-    context 'default' do
-      let(:get_var_expects) { nil }
-
-      its(:spacing) { should == Sass::Script::Number.new(0).value }
-    end
-  end
-
-  describe '#offset' do
-    before { image.stubs(:position).returns(stub_position) }
-
-    let(:offset) { 100 }
-    let(:stub_position) {
-      stub(:value => offset)
-    }
-
-    context 'unitless' do
-      before { stub_position.stubs(:unitless?).returns(true) }
-      before { stub_position.stubs(:unit_str).returns('em') }
-
-      its(:offset) { should == offset }
-    end
-
-    context 'pixels' do
-      before { stub_position.stubs(:unitless?).returns(false) }
-      before { stub_position.stubs(:unit_str).returns('px') }
-
-      its(:offset) { should == offset }
-    end
-
-    context 'neither, use 0' do
-      before { stub_position.stubs(:unitless?).returns(false) }
-      before { stub_position.stubs(:unit_str).returns('em') }
-
-      its(:offset) { should == 0 }
-    end
-  end
-end
diff --git a/spec/compass/sass_extensions/sprites/sprite_map_spec.rb b/spec/compass/sass_extensions/sprites/sprite_map_spec.rb
deleted file mode 100644
index 30a3895d..00000000
--- a/spec/compass/sass_extensions/sprites/sprite_map_spec.rb
+++ /dev/null
@@ -1,54 +0,0 @@
-require 'spec_helper'
-require 'fakefs/spec_helpers'
-require 'timecop'
-
-describe Compass::SpriteImporter do
-  include FakeFS::SpecHelpers
-
-  let(:sprite_map) { self.class.describes.new(uri, options) }
-  let(:options) { { :test => :test2 } }
-
-  subject { sprite_map }
-
-  let(:path) { 'path' }
-  let(:dir) { "dir/#{name}" }
-  let(:name) { 'subdir' }
-
-  let(:sprite_path) { File.join(path, dir) }
-  let(:files) { (1..3).collect { |i| File.join(sprite_path, "#{i}.png") } }
-  let(:expanded_files) { files.collect { |file| File.expand_path(file) } }
-
-  let(:configuration) { stub(:images_path => path) }
-  let(:mtime) { Time.now - 30 }
-
-  before {
-    Compass.stubs(:configuration).returns(configuration)
-
-    FileUtils.mkdir_p(sprite_path)
-    Timecop.freeze(mtime) do
-      files.each { |file| File.open(file, 'w') }
-    end
-    Timecop.return
-  }
-
-  describe '#initialize' do
-    let(:uri) { 'dir/subdir/*.png' }
-
-    its(:uri) { should == uri }
-    its(:path) { should == dir }
-    its(:name) { should == name }
-
-    its(:files) { should == expanded_files }
-
-    its(:sass_options) { should == options.merge(:filename => name, :syntax => :scss, :importer => sprite_map) }
-
-
-    it "should have a correct mtime" do
-      sprite_map.mtime(uri, subject.sass_options).should == mtime
-    end
-
-    it "should have a test for the sass engine" do
-      pending 'sass'
-    end
-  end
-end
diff --git a/spec/compass/sass_extensions/sprites/sprites_spec.rb b/spec/compass/sass_extensions/sprites/sprites_spec.rb
deleted file mode 100644
index 9246d8d3..00000000
--- a/spec/compass/sass_extensions/sprites/sprites_spec.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-require 'spec_helper'
-require 'fakefs/spec_helpers'
-
-describe Compass::Sprites do
-end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
deleted file mode 100644
index 9fee20ea..00000000
--- a/spec/spec_helper.rb
+++ /dev/null
@@ -1,37 +0,0 @@
-$LOAD_PATH.unshift(File.dirname(__FILE__))
-$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
-require 'rubygems'
-require 'compass'
-require 'rspec'
-require 'rspec/autorun'
-require 'mocha'
-
-module CompassGlobalInclude
-  class << self
-    def included(klass)
-      klass.instance_eval do
-        let(:images_src_path) { File.join(File.dirname(__FILE__), 'test_project', 'public', 'images') }
-      end
-    end
-  end
-end
-
-module CompassSpriteHelpers
-  def create_sprite_temp
-    ::FileUtils.cp_r @images_src_path, @images_tmp_path
-  end
-
-  def clean_up_sprites
-    ::FileUtils.rm_r @images_tmp_path
-  end
-end
-
-RSpec.configure do |config|
-  config.include(CompassGlobalInclude)
-  config.include(CompassSpriteHelpers)
-  config.before :each do
-    @images_src_path = File.join(File.dirname(__FILE__), 'test_project', 'public', 'images')
-    @images_tmp_path = File.join(File.dirname(__FILE__), 'test_project', 'public', 'images-tmp')
-  end
-  config.mock_with :mocha
-end
\ No newline at end of file
diff --git a/spec/sprites_spec.rb b/spec/sprites_spec.rb
deleted file mode 100644
index 2b39c8a3..00000000
--- a/spec/sprites_spec.rb
+++ /dev/null
@@ -1,571 +0,0 @@
-require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
-require 'digest/md5'
-
-describe Compass::Sprites do
-
-  before :each do
-    create_sprite_temp
-    file = StringIO.new("images_path = #{@images_tmp_path.inspect}\n")
-    Compass.add_configuration(file, "sprite_config")
-    Compass.configure_sass_plugin!
-  end
-
-  after :each do
-    clean_up_sprites
-  end
-
-  def map_location(file)
-    Dir.glob(File.join(@images_tmp_path, file)).first
-  end
-
-  def image_size(file)
-    IO.read(map_location(file))[0x10..0x18].unpack('NN')
-  end
-
-  def image_md5(file)
-    md5 = Digest::MD5.new
-    md5.update IO.read(map_location(file))
-    md5.hexdigest
-  end
-
-  def render(scss)
-    scss = %Q(@import "compass"; #{scss})
-    options = Compass.sass_engine_options
-    options[:line_comments] = false
-    options[:style] = :expanded
-    options[:syntax] = :scss
-    css = Sass::Engine.new(scss, options).render
-    # reformat to fit result of heredoc:
-    "      #{css.gsub('@charset "UTF-8";', '').gsub(/\n/, "\n      ").strip}\n"
-  end
-
-  #Callbacks
-  describe 'callbacks' do
-    it "should fire on_sprite_saved" do
-      saved = false
-      path = nil
-      Compass.configuration.on_sprite_saved {|filepath| path = filepath; saved = true }
-      render <<-SCSS
-        @import "squares/*.png";
-        @include all-squares-sprites;
-      SCSS
-      saved.should eq true
-      path.should be_kind_of String
-    end
-    it "should fire on_sprite_generated" do
-      saved = false
-      sprite_data = nil
-      Compass.configuration.on_sprite_generated {|data| sprite_data = data; saved = true }
-      render <<-SCSS
-        @import "squares/*.png";
-        @include all-squares-sprites;
-      SCSS
-      sprite_data.should be_kind_of ChunkyPNG::Image
-      saved.should eq true
-    end
-  end
-
-  # DEFAULT USAGE:
-  it "should generate sprite classes" do
-    css = render <<-SCSS
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-161c60ad78.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -10px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-    image_md5('squares-*.png').should == 'fcc93d7b279c2ad6898fbca49cbd01e1'
-  end
-
-  it "should generate sprite classes with dimensions" do
-    css = render <<-SCSS
-      $squares-sprite-dimensions: true;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-161c60ad78.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-        height: 10px;
-        width: 10px;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -10px;
-        height: 20px;
-        width: 20px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-  end
-
-  it "should provide sprite mixin" do
-    css = render <<-SCSS
-      @import "squares/*.png";
-
-      .cubicle {
-        @include squares-sprite("ten-by-ten");
-      }
-
-      .large-cube {
-        @include squares-sprite("twenty-by-twenty", true);
-      }
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .cubicle, .large-cube {
-        background: url('/squares-161c60ad78.png') no-repeat;
-      }
-      
-      .cubicle {
-        background-position: 0 0;
-      }
-      
-      .large-cube {
-        background-position: 0 -10px;
-        height: 20px;
-        width: 20px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-  end
-
-  # CUSTOMIZATIONS:
-
-  it "should be possible to change the base class" do
-    css = render <<-SCSS
-      $squares-sprite-base-class: ".circles";
-      @import "squares/*.png";
-    SCSS
-    css.should == <<-CSS
-      .circles {
-        background: url('/squares-161c60ad78.png') no-repeat;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-  end
-
-  it "should calculate the spacing between images but not before first image" do
-    css = render <<-SCSS
-      $squares-ten-by-ten-spacing: 33px;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-89450808af.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -43px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 63]
-  end
-
-  it "should calculate the spacing between images" do
-    css = render <<-SCSS
-      $squares-twenty-by-twenty-spacing: 33px;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-673837183a.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -43px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 63]
-  end
-
-  it "should calculate the maximum spacing between images" do
-    css = render <<-SCSS
-      $squares-ten-by-ten-spacing: 44px;
-      $squares-twenty-by-twenty-spacing: 33px;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-1cd84c9068.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -54px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 74]
-  end
-
-  it "should calculate the maximum spacing between images in reversed order" do
-    css = render <<-SCSS
-      $squares-ten-by-ten-spacing: 33px;
-      $squares-twenty-by-twenty-spacing: 44px;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-f25b7090ca.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -54px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 74]
-  end
-
-  it "should calculate the default spacing between images" do
-    css = render <<-SCSS
-      $squares-spacing: 22px;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-d66bf24bab.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -32px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 52]
-  end
-
-  it "should use position adjustments in functions" do
-    css = render <<-SCSS
-      $squares: sprite-map("squares/*.png", $position: 100%);
-      .squares-sprite {
-        background: $squares no-repeat;
-      }
-
-      .adjusted-percentage {
-        background-position: sprite-position($squares, ten-by-ten, 100%);
-      }
-
-      .adjusted-px-1 {
-        background-position: sprite-position($squares, ten-by-ten, 4px);
-      }
-
-      .adjusted-px-2 {
-        background-position: sprite-position($squares, twenty-by-twenty, -3px, 2px);
-      }
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite {
-        background: url('/squares-8e490168dd.png') no-repeat;
-      }
-      
-      .adjusted-percentage {
-        background-position: 100% 0;
-      }
-      
-      .adjusted-px-1 {
-        background-position: -6px 0;
-      }
-      
-      .adjusted-px-2 {
-        background-position: -3px -8px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-    image_md5('squares-*.png').should == '652b67f5e9092520d6f26caae7e18012'
-  end
-
-  it "should use position adjustments in mixins" do
-    css = render <<-SCSS
-      $squares-position: 100%;
-      @import "squares/*.png";
-
-      .adjusted-percentage {
-        @include squares-sprite("ten-by-ten", $offset-x: 100%);
-      }
-
-      .adjusted-px-1 {
-        @include squares-sprite("ten-by-ten", $offset-x: 4px);
-      }
-
-      .adjusted-px-2 {
-        @include squares-sprite("twenty-by-twenty", $offset-x: -3px, $offset-y: 2px);
-      }
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .adjusted-percentage, .adjusted-px-1, .adjusted-px-2 {
-        background: url('/squares-8e490168dd.png') no-repeat;
-      }
-      
-      .adjusted-percentage {
-        background-position: 100% 0;
-      }
-      
-      .adjusted-px-1 {
-        background-position: -6px 0;
-      }
-      
-      .adjusted-px-2 {
-        background-position: -3px -8px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-    image_md5('squares-*.png').should == '652b67f5e9092520d6f26caae7e18012'
-  end
-
-  it "should repeat the image" do
-    css = render <<-SCSS
-      $squares-repeat: repeat;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-a5550fd132.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: 0 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: 0 -10px;
-      }
-    CSS
-    image_size('squares-*.png').should == [20, 30]
-    image_md5('squares-*.png').should == '94abae8440f1b58617f52920b70aaed2'
-  end
-
-  it "should allow the position of a sprite to be specified in absolute pixels" do
-    css = render <<-SCSS
-      $squares-ten-by-ten-position: 10px;
-      $squares-twenty-by-twenty-position: 10px;
-      @import "squares/*.png";
-      @include all-squares-sprites;
-    SCSS
-    css.should == <<-CSS
-      .squares-sprite, .squares-ten-by-ten, .squares-twenty-by-twenty {
-        background: url('/squares-89a274044e.png') no-repeat;
-      }
-      
-      .squares-ten-by-ten {
-        background-position: -10px 0;
-      }
-      
-      .squares-twenty-by-twenty {
-        background-position: -10px -10px;
-      }
-    CSS
-    image_size('squares-*.png').should == [30, 30]
-    image_md5('squares-*.png').should == '2fb19ef9c83018c93c6f147af3a56cb2'
-  end
-
-  it "should provide a nice errors for lemonade's old users" do
-    proc do
-      render <<-SCSS
-        .squares {
-          background: sprite-url("squares/*.png") no-repeat;
-        }
-      SCSS
-    end.should raise_error Sass::SyntaxError,
-      %q(The first argument to sprite-url() must be a sprite map. See http://beta.compass-style.org/help/tutorials/spriting/ for more information.)
-    proc do
-      render <<-SCSS
-        .squares {
-          background: sprite-image("squares/twenty-by-twenty.png") no-repeat;
-        }
-      SCSS
-    end.should raise_error Sass::SyntaxError,
-      %q(The sprite-image() function has been replaced by sprite(). See http://beta.compass-style.org/help/tutorials/spriting/ for more information.)
-    proc do
-      render <<-SCSS
-        @import "squares/*.png";
-
-        .squares {
-          background: sprite-position("squares/twenty-by-twenty.png") no-repeat;
-        }
-      SCSS
-    end.should raise_error Sass::SyntaxError,
-      %q(The first argument to sprite-position() must be a sprite map. See http://beta.compass-style.org/help/tutorials/spriting/ for more information.)
-  end
-
-  it "should work even if @import is missing" do
-    actual_css = render <<-SCSS
-      .squares {
-        background: sprite(sprite-map("squares/*.png"), twenty-by-twenty) no-repeat;
-      }
-    SCSS
-    actual_css.should == <<-CSS
-      .squares {
-        background: url('/squares-145869726f.png') 0 -10px no-repeat;
-      }
-    CSS
-  end
-  
-  it "should calculate corret sprite demsions when givin spacing via issue#253" do
-    css = render <<-SCSS
-      $squares-spacing: 10px;
-      @import "squares/*.png";
-      .foo {
-        @include sprite-background-position($squares-sprites, "twenty-by-twenty");
-      }
-      .bar {
-        @include sprite-background-position($squares-sprites, "ten-by-ten");
-      }
-    SCSS
-    image_size('squares-*.png').should == [20, 40]
-    css.should == <<-CSS
-      .squares-sprite {
-        background: url('/squares-e3c68372d9.png') no-repeat;
-      }
-      
-      .foo {
-        background-position: 0 -20px;
-      }
-      
-      .bar {
-        background-position: 0 0;
-      }
-    CSS
-  end
-
-  it "should render corret sprite with css selectors via issue#248" do
-    css = render <<-SCSS
-      @import "selectors/*.png";
-      @include all-selectors-sprites;
-    SCSS
-    css.should == <<-CSS
-      .selectors-sprite, .selectors-ten-by-ten {
-        background: url('/selectors-edfef809e2.png') no-repeat;
-      }
-      
-      .selectors-ten-by-ten {
-        background-position: 0 0;
-      }
-      .selectors-ten-by-ten:hover, .selectors-ten-by-ten.ten-by-ten_hover, .selectors-ten-by-ten.ten-by-ten-hover {
-        background-position: 0 -20px;
-      }
-      .selectors-ten-by-ten:target, .selectors-ten-by-ten.ten-by-ten_target, .selectors-ten-by-ten.ten-by-ten-target {
-        background-position: 0 -30px;
-      }
-      .selectors-ten-by-ten:active, .selectors-ten-by-ten.ten-by-ten_active, .selectors-ten-by-ten.ten-by-ten-active {
-        background-position: 0 -10px;
-      }
-    CSS
-  end
-
-  it "should render corret sprite with css selectors via magic mixin" do
-    css = render <<-SCSS
-      @import "selectors/*.png";
-      a {
-        @include selectors-sprite(ten-by-ten)
-      }
-    SCSS
-    css.should == <<-CSS
-      .selectors-sprite, a {
-        background: url('/selectors-edfef809e2.png') no-repeat;
-      }
-      
-      a {
-        background-position: 0 0;
-      }
-      a:hover, a.ten-by-ten_hover, a.ten-by-ten-hover {
-        background-position: 0 -20px;
-      }
-      a:target, a.ten-by-ten_target, a.ten-by-ten-target {
-        background-position: 0 -30px;
-      }
-      a:active, a.ten-by-ten_active, a.ten-by-ten-active {
-        background-position: 0 -10px;
-      }
-    CSS
-  end
-  
-  it "should not render corret sprite with css selectors via magic mixin" do
-    css = render <<-SCSS
-      @import "selectors/*.png";
-      a {
-        $disable-magic-sprite-selectors:true;
-        @include selectors-sprite(ten-by-ten)
-      }
-    SCSS
-    css.should == <<-CSS
-      .selectors-sprite, a {
-        background: url('/selectors-edfef809e2.png') no-repeat;
-      }
-      
-      a {
-        background-position: 0 0;
-      }
-    CSS
-  end
-  
-  it "should raise error on filenames that are not valid sass syntax" do
-    lambda do
-      render <<-SCSS
-        @import "prefix/*.png";
-        a {
-          @include squares-sprite(20-by-20);
-        }
-      SCSS
-    end.should raise_error Compass::Error
-  end
-
-  it "should generate sprite with bad repeat-x dimensions" do
-    css = render <<-SCSS
-      $ko-starbg26x27-repeat: repeat-x;
-      @import "ko/*.png";
-      @include all-ko-sprites;
-    SCSS
-    css.should == <<-CSS
-      .ko-sprite, .ko-default_background, .ko-starbg26x27 {
-        background: url('/ko-cc3f80660d.png') no-repeat;
-      }
-      
-      .ko-default_background {
-        background-position: 0 0;
-      }
-      
-      .ko-starbg26x27 {
-        background-position: 0 -128px;
-      }
-    CSS
-  end
-
-end
diff --git a/spec/test_project/public/images/ko/default_background.png b/spec/test_project/public/images/ko/default_background.png
deleted file mode 100644
index b98cd7f9..00000000
Binary files a/spec/test_project/public/images/ko/default_background.png and /dev/null differ
diff --git a/spec/test_project/public/images/ko/starbg26x27.png b/spec/test_project/public/images/ko/starbg26x27.png
deleted file mode 100755
index 48dee0db..00000000
Binary files a/spec/test_project/public/images/ko/starbg26x27.png and /dev/null differ
diff --git a/spec/test_project/public/images/prefix/20-by-20.png b/spec/test_project/public/images/prefix/20-by-20.png
deleted file mode 100644
index 4e5e297f..00000000
Binary files a/spec/test_project/public/images/prefix/20-by-20.png and /dev/null differ
diff --git a/spec/test_project/public/images/prefix/ten-by-ten.png b/spec/test_project/public/images/prefix/ten-by-ten.png
deleted file mode 100644
index c0ae53cc..00000000
Binary files a/spec/test_project/public/images/prefix/ten-by-ten.png and /dev/null differ
diff --git a/spec/test_project/public/images/selectors/ten-by-ten.png b/spec/test_project/public/images/selectors/ten-by-ten.png
deleted file mode 100644
index c0ae53cc..00000000
Binary files a/spec/test_project/public/images/selectors/ten-by-ten.png and /dev/null differ
diff --git a/spec/test_project/public/images/selectors/ten-by-ten_active.png b/spec/test_project/public/images/selectors/ten-by-ten_active.png
deleted file mode 100644
index c0ae53cc..00000000
Binary files a/spec/test_project/public/images/selectors/ten-by-ten_active.png and /dev/null differ
diff --git a/spec/test_project/public/images/selectors/ten-by-ten_hover.png b/spec/test_project/public/images/selectors/ten-by-ten_hover.png
deleted file mode 100644
index c0ae53cc..00000000
Binary files a/spec/test_project/public/images/selectors/ten-by-ten_hover.png and /dev/null differ
diff --git a/spec/test_project/public/images/selectors/ten-by-ten_target.png b/spec/test_project/public/images/selectors/ten-by-ten_target.png
deleted file mode 100644
index c0ae53cc..00000000
Binary files a/spec/test_project/public/images/selectors/ten-by-ten_target.png and /dev/null differ
diff --git a/spec/test_project/public/images/squares/ten-by-ten.png b/spec/test_project/public/images/squares/ten-by-ten.png
deleted file mode 100644
index c0ae53cc..00000000
Binary files a/spec/test_project/public/images/squares/ten-by-ten.png and /dev/null differ
diff --git a/spec/test_project/public/images/squares/twenty-by-twenty.png b/spec/test_project/public/images/squares/twenty-by-twenty.png
deleted file mode 100644
index 4e5e297f..00000000
Binary files a/spec/test_project/public/images/squares/twenty-by-twenty.png and /dev/null differ
diff --git a/test/fixtures/stylesheets/busted_image_urls/config.rb b/test/fixtures/stylesheets/busted_image_urls/config.rb
new file mode 100644
index 00000000..13821b8e
--- /dev/null
+++ b/test/fixtures/stylesheets/busted_image_urls/config.rb
@@ -0,0 +1,29 @@
+# Require any additional compass plugins here.
+project_type = :stand_alone
+css_dir = "tmp"
+sass_dir = "sass"
+images_dir = "images"
+output_style = :compact
+# To enable relative image paths using the images_url() function:
+# http_images_path = :relative
+http_images_path = "/images"
+line_comments = false
+
+asset_cache_buster do |path, file|
+  pathname = Pathname.new(path)
+  
+  case pathname.basename(pathname.extname).to_s
+  when "grid"
+    new_path = "%s/%s-BUSTED%s" % [pathname.dirname, pathname.basename(pathname.extname), pathname.extname]
+    {:path => new_path, :query => nil}
+  when "feed"
+    "query_string"
+  when "dk"
+    {:query => "query_string"}
+  end
+end
+
+
+asset_host do |path|
+  "http://assets%d.example.com" % (path.size % 4)
+end
diff --git a/test/fixtures/stylesheets/busted_image_urls/css/screen.css b/test/fixtures/stylesheets/busted_image_urls/css/screen.css
new file mode 100644
index 00000000..ab36dbc7
--- /dev/null
+++ b/test/fixtures/stylesheets/busted_image_urls/css/screen.css
@@ -0,0 +1,9 @@
+.showgrid { background-image: url('http://assets0.example.com/images/grid-BUSTED.png'); }
+
+.inlinegrid { background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACgAAAAUEAYAAACv1qP4AAAABmJLR0T///////8JWPfcAAAACXBIWXMAAABIAAAASABGyWs+AAAAZ0lEQVRYw+3QwQ2AIBAFUTEUwI3+uzN7gDscsIgxEuO8An52J11X73OudfxMraXkzHfO3Y98nQEhA0IGhAwIGRAyIGRAyICQASEDQgaEDAgZEDIgZEDIgJABoZzSGK3tPuN9ERFP7Nw4fg+c5g8V1wAAAABJRU5ErkJggg=='); }
+
+.no-buster { background-image: url('http://assets0.example.com/images/grid.png'); }
+
+.feed { background-image: url('http://assets0.example.com/images/feed.png?query_string'); }
+
+.dk { background-image: url('http://assets0.example.com/images/flags/dk.png?query_string'); }
diff --git a/test/fixtures/stylesheets/busted_image_urls/images/feed.png b/test/fixtures/stylesheets/busted_image_urls/images/feed.png
new file mode 100644
index 00000000..315c4f4f
Binary files /dev/null and b/test/fixtures/stylesheets/busted_image_urls/images/feed.png differ
diff --git a/test/fixtures/stylesheets/busted_image_urls/images/flags/dk.png b/test/fixtures/stylesheets/busted_image_urls/images/flags/dk.png
new file mode 100644
index 00000000..5f660619
Binary files /dev/null and b/test/fixtures/stylesheets/busted_image_urls/images/flags/dk.png differ
diff --git a/test/fixtures/stylesheets/busted_image_urls/images/grid.png b/test/fixtures/stylesheets/busted_image_urls/images/grid.png
new file mode 100644
index 00000000..76aaa851
Binary files /dev/null and b/test/fixtures/stylesheets/busted_image_urls/images/grid.png differ
diff --git a/test/fixtures/stylesheets/busted_image_urls/sass/screen.sass b/test/fixtures/stylesheets/busted_image_urls/sass/screen.sass
new file mode 100644
index 00000000..b469b120
--- /dev/null
+++ b/test/fixtures/stylesheets/busted_image_urls/sass/screen.sass
@@ -0,0 +1,14 @@
+.showgrid
+  background-image: image-url("grid.png")
+
+.inlinegrid
+  background-image: inline-image("grid.png")
+
+.no-buster
+  background-image: image-url("grid.png", $only-path: false, $cache-buster: false)
+
+.feed
+  background-image: image-url("feed.png")
+
+.dk
+  background-image: image-url("flags/dk.png")
\ No newline at end of file
diff --git a/test/fixtures/stylesheets/compass/css/legacy_clearfix.css b/test/fixtures/stylesheets/compass/css/legacy_clearfix.css
index 2a287628..54086726 100644
--- a/test/fixtures/stylesheets/compass/css/legacy_clearfix.css
+++ b/test/fixtures/stylesheets/compass/css/legacy_clearfix.css
@@ -15,3 +15,12 @@
     visibility: hidden; }
   .pie-clearfix {
     display: block; }
+
+.simplified-pie-clearfix {
+  display: inline-block; }
+  .simplified-pie-clearfix:after {
+    content: "";
+    display: table;
+    clear: both; }
+  .simplified-pie-clearfix {
+    display: block; }
diff --git a/test/fixtures/stylesheets/compass/css/utilities.css b/test/fixtures/stylesheets/compass/css/utilities.css
index 354c84dc..8a6c64b1 100644
--- a/test/fixtures/stylesheets/compass/css/utilities.css
+++ b/test/fixtures/stylesheets/compass/css/utilities.css
@@ -12,6 +12,13 @@
     overflow: hidden;
     visibility: hidden; }
 
+.simple-pie-clearfix {
+  *zoom: 1; }
+  .simple-pie-clearfix:after {
+    content: "";
+    display: table;
+    clear: both; }
+
 p.light {
   background-color: #b0201e;
   color: black; }
diff --git a/test/fixtures/stylesheets/compass/sass/legacy_clearfix.scss b/test/fixtures/stylesheets/compass/sass/legacy_clearfix.scss
index 5a9f6396..906e49b1 100644
--- a/test/fixtures/stylesheets/compass/sass/legacy_clearfix.scss
+++ b/test/fixtures/stylesheets/compass/sass/legacy_clearfix.scss
@@ -7,5 +7,8 @@ $default-has-layout-approach: block;
 }
 
 .pie-clearfix {
+    @include legacy-pie-clearfix;
+}
+.simplified-pie-clearfix {
     @include pie-clearfix;
 }
diff --git a/test/fixtures/stylesheets/compass/sass/utilities.scss b/test/fixtures/stylesheets/compass/sass/utilities.scss
index 7daac2f6..d579a6ca 100644
--- a/test/fixtures/stylesheets/compass/sass/utilities.scss
+++ b/test/fixtures/stylesheets/compass/sass/utilities.scss
@@ -5,7 +5,10 @@
 }
 
 .pie-clearfix {
-    @include pie-clearfix;
+    @include legacy-pie-clearfix;
+}
+.simple-pie-clearfix {
+  @include pie-clearfix;
 }
 
 p.light { @include contrasted(#B0201E); }
diff --git a/test/integrations/compass_test.rb b/test/integrations/compass_test.rb
index c8f4f5f8..b505debb 100644
--- a/test/integrations/compass_test.rb
+++ b/test/integrations/compass_test.rb
@@ -73,6 +73,17 @@ class CompassTest < Test::Unit::TestCase
     end
   end
 
+  def test_busted_image_urls
+    within_project('busted_image_urls') do |proj|
+      each_css_file(proj.css_path) do |css_file|
+        assert_no_errors css_file, 'busted_image_urls'
+      end
+      each_sass_file do |sass_file|
+        assert_renders_correctly sass_file
+      end
+    end
+  end
+
   def test_image_urls
     within_project('image_urls') do |proj|
       each_css_file(proj.css_path) do |css_file|
diff --git a/test/integrations/sprites_test.rb b/test/integrations/sprites_test.rb
index 126ad8c3..723dac7d 100644
--- a/test/integrations/sprites_test.rb
+++ b/test/integrations/sprites_test.rb
@@ -71,7 +71,7 @@ class SpritesTest < Test::Unit::TestCase
       }
     CSS
     assert_equal image_size('squares-s*.png'), [20, 30]
-    assert_equal image_md5('squares-s*.png'), 'fcc93d7b279c2ad6898fbca49cbd01e1'
+    assert_equal image_md5('squares-s*.png'), '7349a0f4e88ea80abddcf6ac2486abe3'
   end
 
   it "should generate sprite classes with dimensions" do
@@ -294,7 +294,7 @@ class SpritesTest < Test::Unit::TestCase
       }
     CSS
     assert_equal image_size('squares-s*.png'), [20, 30]
-    assert_equal image_md5('squares-s*.png'), '652b67f5e9092520d6f26caae7e18012'
+    assert_equal image_md5('squares-s*.png'), '9cc7ce48cfaf304381c2d08adefd2fb6'
   end
 
   it "should use position adjustments in mixins" do
@@ -332,7 +332,7 @@ class SpritesTest < Test::Unit::TestCase
       }
     CSS
     assert_equal image_size('squares-s*.png'), [20, 30]
-    assert_equal image_md5('squares-s*.png'), '652b67f5e9092520d6f26caae7e18012'
+    assert_equal image_md5('squares-s*.png'), '9cc7ce48cfaf304381c2d08adefd2fb6'
   end
 
   it "should repeat the image" do
@@ -355,7 +355,7 @@ class SpritesTest < Test::Unit::TestCase
       }
     CSS
     assert_equal image_size('squares-s*.png'), [20, 30]
-    assert_equal image_md5('squares-s*.png'), '94abae8440f1b58617f52920b70aaed2'
+    assert_equal image_md5('squares-s*.png'), 'a77a2fd43f04d791722b706aa7c9f1c1'
   end
 
   it "should allow the position of a sprite to be specified in absolute pixels" do
@@ -379,7 +379,7 @@ class SpritesTest < Test::Unit::TestCase
       }
     CSS
     assert_equal image_size('squares-s*.png'), [30, 30]
-    assert_equal image_md5('squares-s*.png'), '2fb19ef9c83018c93c6f147af3a56cb2'
+    assert_equal image_md5('squares-s*.png'), '9856ced9e8211b6b28ff782019a0d905'
   end
 
   it "should provide a nice errors for lemonade's old users" do
diff --git a/test/units/sprites/engine_test.rb b/test/units/sprites/engine_test.rb
new file mode 100644
index 00000000..a172c518
--- /dev/null
+++ b/test/units/sprites/engine_test.rb
@@ -0,0 +1,43 @@
+require 'test_helper'
+
+class EngineTest < Test::Unit::TestCase
+  
+  def setup
+    sprite_filename = 'squares/ten-by-ten.png'
+    @images = [
+       Compass::SassExtensions::Sprites::Image.new(nil, File.join(sprite_filename), {}) 
+      ]
+    @engine = Compass::SassExtensions::Sprites::Engine.new(100, 100, @images)
+  end
+  
+  
+  test "should have width of 100" do
+    assert_equal 100, @engine.width
+  end
+  
+  test "should have height of 100" do
+    assert_equal 100, @engine.height
+  end
+  
+  test "should have correct images" do
+    assert_equal @images, @engine.images
+  end
+  
+  test "raises Compass::Error when calling save" do
+    begin 
+      @engine.save('foo')
+      assert false, '#save did not raise an exception'
+    rescue Compass::Error
+      assert true
+    end
+  end
+  
+  test "raises Compass::Error when calling construct_sprite" do
+    begin 
+      @engine.construct_sprite
+      assert false, '#construct_sprite did not raise an exception'
+    rescue Compass::Error
+      assert true
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/units/sprites/importer_test.rb b/test/units/sprites/importer_test.rb
index d25bff1e..79fdc800 100644
--- a/test/units/sprites/importer_test.rb
+++ b/test/units/sprites/importer_test.rb
@@ -9,6 +9,10 @@ class ImporterTest < Test::Unit::TestCase
     Compass.add_configuration(file, "sprite_config")
     @importer = Compass::SpriteImporter.new(:uri => URI, :options => options)
   end
+
+  def teardown
+    Compass.reset_configuration!
+  end
   
   def options
     {:foo => 'bar'}
@@ -46,21 +50,17 @@ class ImporterTest < Test::Unit::TestCase
     assert_equal 'bar', @importer.sass_options[:foo]
   end
   
-  test "should fail givin bad sprite extensions" do
+  test "should fail given bad sprite extensions" do
     @images_src_path = File.join(File.dirname(__FILE__), '..', '..', 'fixtures', 'sprites', 'public', 'images')
     file = StringIO.new("images_path = #{@images_src_path.inspect}\n")
     Compass.add_configuration(file, "sprite_config")
     importer = Compass::SpriteImporter.new(:uri => 'bad_extensions/*.jpg', :options => options)
     begin
       importer.sass_engine
-      assert false, "Somthing happened an invalid sprite file made it past validation"
+      assert false, "An invalid sprite file made it past validation."
     rescue Compass::Error => e
       assert e.message.include?('.png')
     end
   end
   
-  def taredown
-    Compass.reset_configuration!
-  end
-  
 end
\ No newline at end of file
diff --git a/spec/compass/commands/sprite_spec.rb b/test/units/sprites/sprite_command_test.rb
similarity index 54%
rename from spec/compass/commands/sprite_spec.rb
rename to test/units/sprites/sprite_command_test.rb
index 6980dcc5..240b00c3 100644
--- a/spec/compass/commands/sprite_spec.rb
+++ b/test/units/sprites/sprite_command_test.rb
@@ -1,32 +1,11 @@
-require 'spec_helper'
-require 'compass/commands'
-require 'compass/exec'
-require 'compass/commands/sprite'
-describe Compass::Commands::Sprite do
-  def config_data
-    return <<-CONFIG
-      images_path = #{@images_tmp_path.inspect}
-    CONFIG
-  end
+require 'test_helper'
+
+class SpriteCommandTest < Test::Unit::TestCase
+  attr_reader :test_dir
   
-  def create_temp_cli_dir
-    directory = File.join(File.expand_path('../', __FILE__), 'test')
-    ::FileUtils.mkdir_p directory
-     @test_dir = directory
-  end
-  
-  def run_compass_with_options(options)
-    output = 'foo'
-    ::Dir.chdir @test_dir
-    %x{compass #{options.join(' ')}}
-  end
-  
-  def options_to_cli(options)
-    options.map.flatten!
-  end
-  
-  let(:test_dir) { @test_dir }  
-  before :each do
+  def setup
+    @images_src_path = File.join(File.dirname(__FILE__), '..', '..', 'fixtures', 'sprites', 'public', 'images')
+    @images_tmp_path = File.join(File.dirname(__FILE__), '..', '..', 'fixtures', 'sprites', 'public', 'images-tmp')
     @before_dir = ::Dir.pwd
     create_temp_cli_dir
     create_sprite_temp
@@ -34,22 +13,48 @@ describe Compass::Commands::Sprite do
       f << config_data
     end
   end
-  after :each do
+  
+  def create_sprite_temp
+    ::FileUtils.cp_r @images_src_path, @images_tmp_path
+  end
+
+  def clean_up_sprites
+    ::FileUtils.rm_r @images_tmp_path
+  end
+  
+  def config_data
+    return <<-CONFIG
+      images_path = #{@images_tmp_path.inspect}
+    CONFIG
+  end
+
+  def create_temp_cli_dir
+    directory = File.join(File.expand_path('../', __FILE__), 'test')
+    ::FileUtils.mkdir_p directory
+     @test_dir = directory
+  end
+
+  def run_compass_with_options(options)
+    output = 'foo'
+    ::Dir.chdir @test_dir
+    %x{compass #{options.join(' ')}}
+  end
+
+  def options_to_cli(options)
+    options.map.flatten!
+  end
+
+  def teardown
     ::Dir.chdir @before_dir
     clean_up_sprites
     if File.exists?(@test_dir)
       ::FileUtils.rm_r @test_dir
     end
   end
-  
+
   it "should create sprite file" do
-    run_compass_with_options(['sprite', "-f", "stylesheet.scss", "'#{@images_tmp_path}/*.png'"]).to_i.should == 0
-    File.exists?(File.join(test_dir, 'stylesheet.scss')).should be_true
+    assert_equal 0, run_compass_with_options(['sprite', "-f", 'stylesheet.scss', "'#{@images_tmp_path}/*.png'"]).to_i
+    assert File.exists?(File.join(test_dir, 'stylesheet.scss'))
   end
-  
-  it "should fail gracfuly when giving bad arguments" do
-    pending
-  end
-  
-  
+
 end
\ No newline at end of file