fix alt tags and add test. Closes #1341

middleman-core/features/automatic_alt_tags.feature

@@ -0,0 +1,8 @@
+Feature: Automatically detect and insert image dimensions into tags
+  In order to speed up development and appease YSlow
+
+  Scenario: Rendering an image with the feature enabled
+    Given "automatic_alt_tags" feature is "enabled"
+    And the Server is running at "automatic-alt-tags-app"
+    When I go to "/auto-image-sizes.html"
+    Then I should see 'alt="Blank"'

middleman-core/fixtures/automatic-alt-tags-app/source/auto-image-sizes.html.erb

@@ -0,0 +1 @@
+<%= image_tag "blank.gif" %>

middleman-core/lib/middleman-more/extensions/automatic_alt_tags.rb

@@ -1,14 +1,10 @@
 # Automatic Image alt tags from image names extension
 class Middleman::Extensions::AutomaticAltTags < ::Middleman::Extension
-  def initialize(app, options_hash={}, &block)
-    super
-  end
-
   helpers do
     # Override default image_tag helper to automatically insert alt tag
     # containing image name.
 
-    def image_tag(path)
+    def image_tag(path, params={})
       unless path.include?('://')
         params[:alt] ||= ''
 
@@ -25,7 +21,7 @@ class Middleman::Extensions::AutomaticAltTags < ::Middleman::Extension
         end
       end
 
-      super(path)
+      super(path, params)
     end
   end
 end