I'm just trying to get people aware of my new patch. It's a very simple update to TestProcess that allows testing of streaming output. Before my patch TestProcess tries to build an HTML::Document with the Proc instead of the captured output of the Proc. I've put this together against tags/2.3.2.1, but I'm willing to rework it should someone recommend I do it on a different branch.
I decided to write up a bit more of a description: http://www.somethingunimportant.com/2009/04/06/rails-bug-found-while-streaming-output-in-actioncontroller-tests/