Merge pull request #30 from projecthydra/af7

Update test suite to be active-fedora 7.0.0 compatible

spec/units/transcoding_spec.rb

@@ -11,7 +11,7 @@ class GenericFile < ActiveFedora::Base
           m.field "mime_type", :string
       end
 
-      delegate :mime_type, :to => :characterization, :unique => true
+      has_attributes :mime_type, datastream: :characterization, multiple: false
       has_file_datastream 'content', type: ContentDatastream
 
       makes_derivatives do |obj|