added test for diagonal layout

test/units/sprites/sprite_map_test.rb

@@ -90,6 +90,21 @@ class SpriteMapTest < Test::Unit::TestCase
   end
   
 
+  def diagonal
+    opts = @options.merge("layout" => Sass::Script::String.new('diagonal'))
+    sprite_map_test(opts)
+  end
+  
+  it "should generate a diagonal sprite" do
+    base = diagonal
+    base.generate
+    assert_equal 40, base.width
+    assert_equal 40, base.height
+    assert_equal [[0,0], [10,10], [20,20], [30,30]], base.images.map {|i| [i.top, i.left]}
+    assert File.exists?(base.filename)
+    FileUtils.rm base.filename
+  end
+
   # Horizontal tests
   def horizontal
     opts = @options.merge("layout" => Sass::Script::String.new('horizontal'))