Sprite importer now passes the correct filename to the sass engine which was causeing unexpected uris to get returned

This fixes the 'to_tree' error that wasn't really a sass bug it was an error on the sprite importers part

lib/compass/sprite_importer.rb

@@ -19,7 +19,7 @@ module Compass
     end
     
     def find_relative(uri, base, options)
-      find(File.join(base, uri), options)
+      nil
     end
     
     def to_s
@@ -85,13 +85,13 @@ module Compass
     end
     
     # Returns the sass_options for this sprite
-    def self.sass_options(name, importer, options)
-      options.merge!(:filename => name, :syntax => :scss, :importer => importer)
+    def self.sass_options(uri, importer, options)
+      options.merge!(:filename => uri, :syntax => :scss, :importer => importer)
     end
     
     # Returns a Sass::Engine for this sprite object
     def self.sass_engine(uri, name, importer, options)
-      Sass::Engine.new(content_for_images(uri, name, options[:skip_overrides]), sass_options(name, importer, options))
+      Sass::Engine.new(content_for_images(uri, name, options[:skip_overrides]), sass_options(uri, importer, options))
     end
 
     # Generates the Sass for this sprite file

test/units/sprites/importer_test.rb

@@ -68,6 +68,12 @@ class ImporterTest < Test::Unit::TestCase
     assert_equal 'bar', opts[:foo]
   end
   
+  test "verify that the sass_engine passes the correct filename" do
+    importer = Compass::SpriteImporter.new
+    engine = Compass::SpriteImporter.sass_engine(URI, 'foo', importer, options)
+    assert_equal engine.options[:filename], URI
+  end
+  
   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")