File posts in integration test

It seems that my file data is being treating as a string or something.
Has anybody been able to do a file post in an integration test?

NoMethodError (undefined method original_filename' for "#<File: 0x316c300>":String): /app/models/attachment.rb:21:infile=’
/vendor/rails/activerecord/lib/active_record/base.rb:1846:in
send' /vendor/rails/activerecord/lib/active_record/base.rb:1846:inattributes=’
/vendor/rails/activerecord/lib/active_record/base.rb:1845:in
each' /vendor/rails/activerecord/lib/active_record/base.rb:1845:inattributes=’
/vendor/rails/activerecord/lib/active_record/base.rb:1672:in
initialize' /app/models/attachment.rb:11:ininitialize’

Actually, I just found this workaround to a rails bug:

http://dev.rubyonrails.org/ticket/4635