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:in `file='     /vendor/rails/activerecord/lib/active_record/base.rb:1846:in `send'     /vendor/rails/activerecord/lib/active_record/base.rb:1846:in `attributes='     /vendor/rails/activerecord/lib/active_record/base.rb:1845:in `each'     /vendor/rails/activerecord/lib/active_record/base.rb:1845:in `attributes='     /vendor/rails/activerecord/lib/active_record/base.rb:1672:in `initialize'     /app/models/attachment.rb:11:in `initialize'

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

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