Fixed extension interpolation bug when relying on default_style

lib/paperclip/attachment.rb

@@ -108,7 +108,7 @@ def url style = default_style, include_updated_timestamp = true
     # file is stored in the filesystem the path refers to the path of the file
     # on disk. If the file is stored in S3, the path is the "key" part of the
     # URL, and the :bucket option refers to the S3 bucket.
-    def path style = nil #:nodoc:
+    def path style = default_style
       original_filename.nil? ? nil : interpolate(@path, style)
     end
 

test/attachment_test.rb

@@ -114,6 +114,20 @@ class AttachmentTest < Test::Unit::TestCase
     end
   end
 
+  context "An attachment with a default style and an extension interpolation" do
+    setup do
+      @attachment = attachment :path => ":basename.:extension",
+                               :styles => { :default => ["100x100", :png] },
+                               :default_style => :default
+      @file = StringIO.new("...")
+      @file.expects(:original_filename).returns("file.jpg")
+    end
+    should "return the right extension for the path" do
+      @attachment.assign(@file)
+      assert_equal "file.png", @attachment.path
+    end
+  end
+
   context "An attachment with :convert_options" do
     setup do
       rebuild_model :styles => {

test/helper.rb

@@ -91,7 +91,7 @@ def errors
     @errors ||= []
   end
 
-  def run_callbacks
+  def run_callbacks name, *args
   end
 end
 

test/interpolations_test.rb

@@ -39,7 +39,7 @@ class InterpolationsTest < Test::Unit::TestCase
     assert_equal "jpg", Paperclip::Interpolations.extension(attachment, :style)
   end
 
-  should "return the extension of the file as the format is defined in the style" do
+  should "return the extension of the file as the format if defined in the style" do
     attachment = mock
     attachment.expects(:original_filename).never
     attachment.expects(:styles).returns({:style => {:format => "png"}})