Well, the page still is not really up to date - actually there are some improvements on the output formatting and a
draft document describing the new features.
The two pieces of httpunit regression testing in ACS 4 that I found - in the templating and the wp-slim package - have been ported from httpunit to tclwebtest and it works so far for me (on an ACS4 Classic system), although these ports are not done in the ideal way (unorganized, one big file instead of a few smaller ones, etc.) The ported tests are in the distribution.
I will do some smaller examples on OpenACS pages soon.