Bolt on lemonade to get started.

Gemfile

@@ -10,3 +10,4 @@ gem "sass", "~> 3.1"
 gem "rcov"
 gem "rubyzip"
 gem "livereload"
+gem "chunky_png"

Rakefile

@@ -29,6 +29,24 @@ To run with an alternate version of Rails, make test/rails a symlink to that ver
 To run with an alternate version of Haml & Sass, make test/haml a symlink to that version.
 END
 
+begin
+  require 'spec/rake/spectask'
+  Spec::Rake::SpecTask.new(:spec) do |spec|
+    spec.libs << 'lib' << 'spec'
+    spec.spec_files = FileList['spec/**/*_spec.rb']
+  end
+
+  Spec::Rake::SpecTask.new(:rcov) do |spec|
+    spec.libs << 'lib' << 'spec'
+    spec.pattern = 'spec/**/*_spec.rb'
+    spec.rcov = true
+  end
+
+  task :default => :spec
+rescue LoadError
+  puts "Rspec (or a dependency) is not available. Try running bundler install"
+end
+
 desc "Compile Examples into HTML and CSS"
 task :examples do
   linked_haml = "tests/haml"

frameworks/compass/stylesheets/_lemonade.scss

@@ -0,0 +1,38 @@
+@mixin image-dimensions($file) {
+  height: image-height($file);
+  width: image-width($file);
+}
+
+@mixin sprite-image($file) {
+  background: sprite-image($file) $repeat;
+}
+
+@mixin sized-sprite-image($file) {
+  background: sprite-image($file);  
+  @include image-dimensions($file);
+}
+
+@mixin sprite-folder($folder, $image-dimensions: false) {
+  .#{$folder} {
+    @if $image-dimensions {
+      background: sprite-url($folder);
+    }
+    @else {
+      background: sprite-url($folder) no-repeat;
+    }
+  }
+  @for $i from 0 to sprite-files-in-folder($folder) {
+    $file: sprite-file-from-folder($folder, $i);
+    .#{$folder}-#{image-basename($file)} {
+      @extend .#{$folder};
+      background-position: sprite-position(sprite-file-from-folder($folder, $i));
+      @if $image-dimensions {
+        @include image-dimensions($file);
+      }
+    }
+  }
+}
+
+@mixin sized-sprite-folder($folder) {
+  @include sprite-folder($folder, true);
+}

lib/compass.rb

@@ -18,3 +18,5 @@ end
 %w(configuration frameworks app_integration actions compiler).each do |lib|
   require "compass/#{lib}"
 end
+
+require "lemonade"

lib/lemonade.rb

@@ -0,0 +1,127 @@
+require 'chunky_png'
+require 'lemonade/sprite_info.rb'
+
+module Lemonade
+  @@sprites = {}
+  @@sprites_path = nil
+  @@images_path = nil
+
+  class << self
+
+    def sprites
+      @@sprites
+    end
+
+    def sprites_path
+      @@sprites_path || images_path
+    end
+
+    def sprites_path=(path)
+      @@sprites_path = path
+    end
+
+    def images_path
+      @@images_path || (defined?(Compass) ? Compass.configuration.images_path : 'public/images')
+    end
+
+    def images_path=(path)
+      @@images_path = path
+    end
+
+    def reset
+      @@sprites = {}
+    end
+
+    def generate_sprites
+      sprites.each do |sprite_name, sprite|
+        calculate_sprite sprite
+        if sprite_changed?(sprite_name, sprite)
+          generate_sprite_image sprite
+          remember_sprite_info! sprite_name, sprite
+        end
+      end
+    end
+
+    def extend_sass!
+      require 'sass'
+      require 'sass/plugin'
+      require File.expand_path('../lemonade/sass_functions', __FILE__)
+      require File.expand_path('../lemonade/sass_extension', __FILE__)
+    end
+    
+    def sprite_changed?(sprite_name, sprite)
+      existing_sprite_info = YAML.load(File.read(sprite_info_file(sprite_name)))
+      existing_sprite_info[:sprite] != sprite or existing_sprite_info[:timestamps] != timestamps(sprite)
+    rescue
+      true
+    end
+
+    def remember_sprite_info!(sprite_name, sprite)
+      File.open(sprite_info_file(sprite_name), 'w') do |file|
+        file << {
+          :sprite => sprite,
+          :timestamps => timestamps(sprite),
+        }.to_yaml
+      end
+    end
+  
+  private
+
+    def sprite_info_file(sprite_name)
+      File.join(Lemonade.images_path, "#{sprite_name}.sprite_info.yml")
+    end
+
+    def timestamps(sprite)
+      result = {}
+      sprite[:images].each do |image|
+        file_name = image[:file]
+        result[file_name] = File.ctime(file_name)
+      end
+      result
+    end
+    
+    def calculate_sprite(sprite)
+      width, margin_bottom, y = 0, 0, 0
+      sprite[:images].each do |sprite_item|
+        if sprite_item[:index] == 0
+          margin_top = 0
+        elsif sprite_item[:margin_top] > margin_bottom
+          margin_top = sprite_item[:margin_top]
+        else
+          margin_top = margin_bottom
+        end
+        y += margin_top
+        sprite_item[:y] = Sass::Script::Number.new(y, ['px'])
+        y += sprite_item[:height]
+        width = sprite_item[:width] if sprite_item[:width] > width
+        margin_bottom = sprite_item[:margin_bottom]
+      end
+      sprite[:height] = y
+      sprite[:width] = width
+    end
+    
+    def generate_sprite_image(sprite)
+      sprite_image = ChunkyPNG::Image.new(sprite[:width], sprite[:height], ChunkyPNG::Color::TRANSPARENT)
+      sprite[:images].each do |sprite_item|
+        sprite_item_image  = ChunkyPNG::Image.from_file(sprite_item[:file])
+        x = (sprite[:width] - sprite_item[:width]) * (sprite_item[:x].value / 100)
+        y = sprite_item[:y].value
+        sprite_image.replace sprite_item_image, x, y
+      end
+      sprite_image.save File.join(Lemonade.images_path, sprite[:file])
+    end
+
+  end
+
+end
+
+
+if defined?(ActiveSupport) and Sass::Util.has?(:public_method, ActiveSupport, :on_load)
+  # Rails 3.0
+  ActiveSupport.on_load :before_initialize do
+    Lemonade.extend_sass!
+  end
+else
+  Lemonade.extend_sass!
+end
+

lib/lemonade/sass_extension.rb

@@ -0,0 +1,21 @@
+module Sass
+
+  module Tree
+
+    class RootNode < Node
+
+      alias_method :render_without_lemonade, :render
+      def render
+        if result = render_without_lemonade
+          Lemonade.generate_sprites
+          result = ERB.new(result).result(binding)
+          Lemonade.reset
+          return result
+        end
+      end
+
+    end
+
+  end
+
+end

lib/lemonade/sass_functions.rb

@@ -0,0 +1,119 @@
+module Sass::Script::Functions
+
+  def sprite_url(file)
+    dir, name, basename = extract_names(file)
+    sprite = sprite_for("#{dir}#{name}")
+    Sass::Script::SpriteInfo.new(:url, sprite)
+  end
+
+  def sprite_position(file, position_x = nil, position_y_shift = nil, margin_top_or_both = nil, margin_bottom = nil)
+    sprite, sprite_item = sprite_url_and_position(file, position_x, position_y_shift, margin_top_or_both, margin_bottom)
+    Sass::Script::SpriteInfo.new(:position, sprite, sprite_item, position_x, position_y_shift)
+  end
+
+  def sprite_image(file, position_x = nil, position_y_shift = nil, margin_top_or_both = nil, margin_bottom = nil)
+    sprite, sprite_item = sprite_url_and_position(file, position_x, position_y_shift, margin_top_or_both, margin_bottom)
+    Sass::Script::SpriteInfo.new(:both, sprite, sprite_item, position_x, position_y_shift)
+  end
+  alias_method :sprite_img, :sprite_image
+
+  def sprite_files_in_folder(folder)
+    assert_type folder, :String
+    count = sprite_file_list_from_folder(folder).length
+    Sass::Script::Number.new(count)
+  end
+
+  def sprite_file_from_folder(folder, n)
+    assert_type folder, :String
+    assert_type n, :Number
+    file = sprite_file_list_from_folder(folder)[n.to_i]
+    file = File.basename(file)
+    Sass::Script::String.new(File.join(folder.value, file))
+  end
+
+  def sprite_name(file)
+    dir, name, basename = extract_names(file)
+    Sass::Script::String.new(name)
+  end
+
+  def image_basename(file)
+    dir, name, basename = extract_names(file, :check_file => true)
+    Sass::Script::String.new(basename)
+  end
+
+private
+
+  def sprite_file_list_from_folder(folder)
+    dir = File.join(Lemonade.sprites_path, folder.value)
+    Dir.glob(File.join(dir, '*.png')).sort
+  end
+
+  def sprite_url_and_position(file, position_x = nil, position_y_shift = nil, margin_top_or_both = nil, margin_bottom = nil)
+    dir, name, basename = extract_names(file, :check_file => true)
+    filestr = File.join(Lemonade.sprites_path, file.value)
+
+    sprite_file = "#{dir}#{name}.png"
+    sprite = sprite_for(sprite_file)
+    sprite_item = image_for(sprite, filestr, position_x, position_y_shift, margin_top_or_both, margin_bottom)
+
+    # Create a temporary destination file so compass doesn't complain about a missing image
+    FileUtils.touch File.join(Lemonade.images_path, sprite_file)
+
+    [sprite, sprite_item]
+  end
+
+  def extract_names(file, options = {})
+    assert_type file, :String
+    unless (file.value =~ %r(^(.+/)?([^\.]+?)(/(.+?)\.(png))?$)) == 0
+      raise Sass::SyntaxError, 'Please provide a file in a folder: e.g. sprites/button.png'
+    end
+    dir, name, basename = $1, $2, $4
+    if options[:check_file] and basename.nil?
+      raise Sass::SyntaxError, 'Please provide a file in a folder: e.g. sprites/button.png'
+    end
+    [dir, name, basename]
+  end
+
+  def sprite_for(file)
+    file = "#{file}.png" unless file =~ /\.png$/
+    Lemonade.sprites[file] ||= {
+        :file => "#{file}",
+        :height => 0,
+        :width => 0,
+        :images => [],
+        :margin_bottom => 0
+      }
+  end
+
+  def image_for(sprite, file, position_x, position_y_shift, margin_top_or_both, margin_bottom)
+    image = sprite[:images].detect{ |image| image[:file] == file }
+    margin_top_or_both ||= Sass::Script::Number.new(0)
+    margin_top = margin_top_or_both.value #calculate_margin_top(sprite, margin_top_or_both, margin_bottom)
+    margin_bottom = (margin_bottom || margin_top_or_both).value
+    if image
+      image[:margin_top] = margin_top if margin_top > image[:margin_top]
+      image[:margin_bottom] = margin_bottom if margin_bottom > image[:margin_bottom]
+    else
+      width, height = ChunkyPNG::Image.from_file(file).size
+      x = (position_x and position_x.numerator_units == %w(%)) ? position_x : Sass::Script::Number.new(0)
+      y = sprite[:height] + margin_top
+      y = Sass::Script::Number.new(y, y == 0 ? [] : ['px'])
+      image = {
+        :file => file,
+        :height => height,
+        :width => width,
+        :x => x,
+        :margin_top => margin_top,
+        :margin_bottom => margin_bottom,
+        :index => sprite[:images].length
+      }
+      sprite[:images] << image
+    end
+    image
+  rescue Errno::ENOENT
+    raise Sass::SyntaxError, "#{file} does not exist in sprites_dir #{Lemonade.sprites_path}"
+  rescue ChunkyPNG::SignatureMismatch
+    raise Sass::SyntaxError, "#{file} is not a recognized png file, can't use for sprite creation"
+  end
+
+end

lib/lemonade/sprite_info.rb

@@ -0,0 +1,63 @@
+require 'sass/script/literal'
+
+module Sass::Script
+
+  class SpriteInfo < Literal
+    attr_reader :sprite
+    attr_reader :sprite_item
+    attr_reader :type
+
+    def initialize(type, sprite, sprite_item = nil, position_x = nil, position_y_shift = nil)
+      super(nil)
+      @type = type
+      @sprite = sprite
+      @sprite_item = sprite_item
+      @position_x = position_x
+      @position_y_shift = position_y_shift
+    end
+
+    def to_s(opts = {})
+      case @type
+      when :position
+        position
+      when :url
+        url
+      when :both
+        pos = position
+        if pos == '0 0'
+          url
+        else
+          "#{url} #{pos}"
+        end
+      end
+    end
+
+    def to_sass
+      to_s
+    end
+
+  private
+
+    def position
+      x = @position_x || 0
+      if @sprite_item[:index] == 0 and (@position_y_shift.nil? or @position_y_shift.value == 0)
+        "#{x.inspect} 0"
+      else
+        expression  = "Lemonade.sprites['#{@sprite[:file]}'][:images][#{@sprite_item[:index]}][:y].unary_minus"
+        expression << ".plus(Sass::Script::Number.new(#{@position_y_shift.value}, ['px']))" if @position_y_shift
+        "#{x.inspect} <%= #{expression} %>"
+      end
+    end
+
+    def url
+      if defined?(Compass)
+        compass = Class.new.extend(Compass::SassExtensions::Functions::Urls)
+        compass.image_url(Sass::Script::String.new(@sprite[:file])).to_s
+      else
+        "url('/#{@sprite[:file]}')"
+      end
+    end
+
+  end
+
+end

lib/lemonade/version.rb

@@ -0,0 +1,3 @@
+module Lemonade
+  Version = "1.0.0.beta.1"
+end

spec/lemonade_spec.rb

@@ -0,0 +1,66 @@
+require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
+
+describe Lemonade do
+
+  before :each do
+    @sprite = {
+      :info => 'info',
+      :images => [
+        { :file => 'file1' },
+        { :file => 'file2' },
+      ]
+    }
+
+    @file = ""
+    File.stub!(:read => @file)
+    Lemonade.stub(:images_path).and_return('image_path')
+    File.stub!(:ctime => Time.parse('2010-01-01 12:00'))
+  end
+
+  ###
+
+  describe '#remember_sprite_info' do
+    subject { Lemonade }
+
+    it 'should save sprite info into a file' do
+      File.should_receive(:open).with(File.join('image_path', 'the_sprite.sprite_info.yml'), 'w').and_yield(@file)
+      @file.should_receive(:<<)
+      subject.remember_sprite_info!('the_sprite', @sprite)
+    end
+  end
+
+  ###
+
+  describe '#sprite_changed?' do
+    subject { Lemonade }
+
+    it 'should be false if nothing changed' do
+      File.should_receive(:open).and_yield(@file)
+      subject.remember_sprite_info!('the sprite', @sprite)
+      subject.sprite_changed?('the sprite', @sprite).should be_false
+    end
+
+    it 'should be true if the sprite info has changed' do
+      File.should_receive(:open).and_yield(@file)
+      subject.remember_sprite_info!('the sprite', @sprite)
+      @sprite[:info] = 'changed info'
+      subject.sprite_changed?('the sprite', @sprite).should be_true
+    end
+
+    it 'should be true if the images changed' do
+      File.should_receive(:open).and_yield(@file)
+      subject.remember_sprite_info!('the sprite', @sprite)
+      @sprite[:images] = []
+      subject.sprite_changed?('the sprite', @sprite).should be_true
+    end
+
+    it 'should be true if a images timestamp changed' do
+      File.should_receive(:open).and_yield(@file)
+      subject.remember_sprite_info!('the sprite', @sprite)
+      File.stub!(:ctime => Time.now)
+      subject.sprite_changed?('the sprite', @sprite).should be_true
+    end
+
+  end
+
+end

spec/sass_functions_spec.rb

@@ -0,0 +1,216 @@
+require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
+
+describe Sass::Script::Functions do
+
+  before :each do
+    Lemonade.reset
+    FileUtils.cp_r File.dirname(__FILE__) + '/images', IMAGES_TMP_PATH
+  end
+
+  after :each do
+    FileUtils.rm_r IMAGES_TMP_PATH
+  end
+
+  def image_size(file)
+    IO.read(IMAGES_TMP_PATH + '/' + file)[0x10..0x18].unpack('NN')
+  end
+
+  def evaluate(*values)
+    sass = 'div' + values.map{ |value| "\n  background: #{value}" }.join
+    css = Sass::Engine.new(sass, :syntax => :sass).render
+    # find rendered CSS values
+    # strip selectors, porperty names, semicolons and whitespace
+    css = css.gsub(/div \{\s*background: (.+?);\s*\}\s*/m, '\\1').split(/;\s*background: /)
+    css = css.first if css.length == 1
+    return css
+  end
+
+  ###
+
+  it "should return the sprite file name" do
+    evaluate('sprite-image("sprites/30x30.png")').should == "url('/sprites.png')"
+  end
+
+  it "should also work with `sprite-img`" do
+    evaluate('sprite-img("sprites/30x30.png")').should == "url('/sprites.png')"
+  end
+
+  it "should work in folders with dashes and underscores" do
+    evaluate('sprite-image("other_images/more-images/sprites/test.png")').should ==
+      "url('/other_images/more-images/sprites.png')"
+  end
+
+  it "should not work without any folder" do
+    lambda { evaluate('sprite-image("test.png")') }.should raise_exception(Sass::SyntaxError)
+  end
+
+  it "should set the background position" do
+    evaluate('sprite-image("sprites/30x30.png") sprite-image("sprites/150x10.png")').should ==
+      "url('/sprites.png') url('/sprites.png') 0 -30px"
+    image_size('sprites.png').should == [150, 40]
+  end
+
+  it "should use the X position" do
+    evaluate('sprite-image("sprites/30x30.png", 5px, 0)').should == "url('/sprites.png') 5px 0"
+    image_size('sprites.png').should == [30, 30]
+  end
+
+  it "should include the Y position" do
+    evaluate('sprite-image("sprites/30x30.png", 0, 3px) sprite-image("sprites/150x10.png", 0, -6px)').should ==
+      "url('/sprites.png') 0 3px url('/sprites.png') 0 -36px"
+  end
+
+  it "should calculate 20px empty space between sprites" do
+    # Resulting sprite should look like (1 line = 10px height, X = placed image):
+
+    # X
+    #
+    #
+    # XX
+    # XX
+    #
+    #
+    # XXX
+    # XXX
+    # XXX
+
+    evaluate(
+      'sprite-image("sprites/10x10.png")',
+      'sprite-image("sprites/20x20.png", 0, 0, 20px)',
+      'sprite-image("sprites/30x30.png", 0, 0, 20px)'
+    ).should == [
+      "url('/sprites.png')",
+      "url('/sprites.png') 0 -30px",
+      "url('/sprites.png') 0 -70px"
+    ]
+    image_size('sprites.png').should == [30, 100]
+  end
+
+  it "should calculate empty space between sprites and combine space like CSS margins" do
+    # Resulting sprite should look like (1 line = 10px height, X = placed image):
+
+    # X
+    #
+    #
+    #
+    # XX
+    # XX
+    #
+    # XXX
+    # XXX
+    # XXX
+
+    evaluate(
+      'sprite-image("sprites/10x10.png", 0, 0, 0, 30px)',
+      'sprite-image("sprites/20x20.png", 0, 0, 20px, 5px)',
+      'sprite-image("sprites/30x30.png", 0, 0, 10px)'
+    ).should == [
+      "url('/sprites.png')",
+      "url('/sprites.png') 0 -40px",
+      "url('/sprites.png') 0 -70px"
+    ]
+    image_size('sprites.png').should == [30, 100]
+  end
+
+  it "should calculate empty space correctly when 2 output images are uses" do
+    evaluate(
+      'sprite-image("sprites/10x10.png", 0, 0, 0, 30px)',
+      'sprite-image("other_images/test.png")',
+      'sprite-image("sprites/20x20.png", 0, 0, 20px, 5px)'
+    ).should == [
+      "url('/sprites.png')",
+      "url('/other_images.png')",
+      "url('/sprites.png') 0 -40px"
+    ]
+  end
+
+  it "should allow % for x positions" do
+    # Resulting sprite should look like (1 line = 10px height, X = placed image):
+
+    # XXXXXXXXXXXXXXX
+    #               X
+
+    evaluate(
+      'sprite-image("sprites/150x10.png")',
+      'sprite-image("sprites/10x10.png", 100%)'
+    ).should == [
+      "url('/sprites.png')",
+      "url('/sprites.png') 100% -10px"
+    ]
+  end
+
+  it "should not compose the same image twice" do
+    evaluate(
+      'sprite-image("sprites/10x10.png")',
+      'sprite-image("sprites/20x20.png")',
+      'sprite-image("sprites/20x20.png")'  # reuse image from line above
+    ).should == [
+      "url('/sprites.png')",
+      "url('/sprites.png') 0 -10px",
+      "url('/sprites.png') 0 -10px"
+    ]
+    image_size('sprites.png').should == [20, 30]
+  end
+
+  it "should calculate the maximum spacing between images" do
+    evaluate(
+      'sprite-image("sprites/10x10.png")',
+      'sprite-image("sprites/20x20.png", 0, 0, 10px)',
+      'sprite-image("sprites/20x20.png", 0, 0, 99px)' # 99px > 10px
+    ).should == [
+      "url('/sprites.png')",
+      "url('/sprites.png') 0 -109px", # use 99px spacing
+      "url('/sprites.png') 0 -109px"
+    ]
+    image_size('sprites.png').should == [20, 129]
+  end
+
+  it "should calculate the maximum spacing between images for margin bottom" do
+    evaluate(
+      'sprite-image("sprites/10x10.png", 0, 0, 0, 10px)',
+      'sprite-image("sprites/10x10.png", 0, 0, 0, 99px)', # 99px > 10px
+      'sprite-image("sprites/20x20.png")'
+    ).should == [
+      "url('/sprites.png')",
+      "url('/sprites.png')",
+      "url('/sprites.png') 0 -109px" # use 99px spacing
+    ]
+    image_size('sprites.png').should == [20, 129]
+  end
+
+  it "should output the background-position" do
+    evaluate(
+      'sprite-position("sprites/10x10.png")',
+      'sprite-position("sprites/20x20.png")'
+    ).should == [
+      "0 0",
+      "0 -10px"
+    ]
+  end
+
+  it "should output the background-image URL" do
+    evaluate('sprite-url("sprites")').should == "url('/sprites.png')"
+    evaluate('sprite-url("sprites/10x10.png")').should == "url('/sprites.png')"
+    evaluate('sprite-url("sprites/20x20.png")').should == "url('/sprites.png')"
+    evaluate('sprite-url("other_images/test.png")').should == "url('/other_images.png')"
+  end
+
+  it "should count the PNG files in a folder" do
+    evaluate('sprite-files-in-folder("sprites")').to_i.should == 4
+  end
+
+  it "should output the n-th file in a folder" do
+    evaluate('sprite-file-from-folder("sprites", 0)').should == "sprites/10x10.png"
+    evaluate('sprite-file-from-folder("sprites", 1)').should == "sprites/150x10.png"
+  end
+
+  it "should output the filename without extention for the sprite" do
+    evaluate('sprite-name("sprites")').should == "sprites"
+    evaluate('sprite-name("sprites/10x10.png")').should == "sprites"
+  end
+
+  it "should output the filename without extention for the sprite item" do
+    evaluate('image-basename("sprites/10x10.png")').should == "10x10"
+  end
+
+end

spec/spec.opts

@@ -0,0 +1,4 @@
+--colour
+--format s
+--loadby mtime
+--reverse

spec/spec_helper.rb

@@ -0,0 +1,14 @@
+$LOAD_PATH.unshift(File.dirname(__FILE__))
+$LOAD_PATH.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
+
+require 'rubygems'
+require 'compass'
+require 'spec'
+require 'spec/autorun'
+
+IMAGES_TMP_PATH = File.join(File.dirname(__FILE__), 'images-tmp')
+Lemonade.images_path = IMAGES_TMP_PATH
+
+Spec::Runner.configure do |config|
+  
+end

spec/sprite_info_spec.rb

@@ -0,0 +1,49 @@
+require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
+
+describe Sass::Script::SpriteInfo do
+
+  def sprite_info(*args)
+    Sass::Script::SpriteInfo.new(*args).to_s
+  end
+
+  ##
+
+  it "should output the position for the first sprite" do
+    sprite = { :file => "sprites.png" }
+    sprite_item = { :y => Sass::Script::Number.new(20, ['px']), :index => 0 }
+    x = Sass::Script::Number.new(10, ['px'])
+    sprite_info(:position, sprite, sprite_item, x).should == "10px 0"
+  end
+
+  it "should output the position for the second+ sprite" do
+    sprite = { :file => "sprites.png" }
+    sprite_item = { :y => Sass::Script::Number.new(20, ['px']), :index => 1 }
+    x = Sass::Script::Number.new(10, ['px'])
+    sprite_info(:position, sprite, sprite_item, x).should == 
+      "10px <%= Lemonade.sprites['sprites.png'][:images][1][:y].unary_minus %>"
+  end
+
+  it "should output the position with y shift" do
+    sprite = { :file => "sprites.png" }
+    sprite_item = { :y => Sass::Script::Number.new(20, ['px']), :index => 1 }
+    x = Sass::Script::Number.new(10, ['px'])
+    y_shift = Sass::Script::Number.new(3, ['px'])
+    sprite_info(:position, sprite, sprite_item, x, y_shift).should == 
+      "10px <%= Lemonade.sprites['sprites.png'][:images][1][:y].unary_minus.plus(Sass::Script::Number.new(3, ['px'])) %>"
+  end
+
+  it "should output the position with percentage" do
+    sprite = { :file => "sprites.png" }
+    sprite_item = { :y => Sass::Script::Number.new(20, ['px']), :index => 2 }
+    x = Sass::Script::Number.new(100, ['%'])
+    sprite_info(:position, sprite, sprite_item, x).should == 
+      "100% <%= Lemonade.sprites['sprites.png'][:images][2][:y].unary_minus %>"
+  end
+
+  it "should output the url" do
+    sprite = { :file => "sprites.png" }
+    sprite_item = { }
+    sprite_info(:url, sprite, sprite_item).should == "url('/sprites.png')"
+  end
+
+end