BUGFIX: broken spec

spec/models/user_avatar_spec.rb

@@ -13,6 +13,10 @@ describe UserAvatar do
 
   it 'can update gravatars' do
     temp = Tempfile.new('test')
+    temp.binmode
+    # tiny valid png
+    temp.write(Base64.decode64("R0lGODlhAQABALMAAAAAAIAAAACAAICAAAAAgIAAgACAgMDAwICAgP8AAAD/AP//AAAA//8A/wD//wBiZCH5BAEAAA8ALAAAAAABAAEAAAQC8EUAOw=="))
+    temp.rewind
     FileHelper.expects(:download).returns(temp)
     avatar.update_gravatar!
     temp.unlink