rspec, rspec_on_rails, ZenTest

Is there any canonical document as to what versions of rspec,
rspec_on_rails and ZenTest should be used for each version of Rails?

I've got a 1.2.6 Rails app and can't find the right mix of these.
Everytime I run "autotest" it bombs on some missing file, or undefined
method, etc.

Any suggestions on what combination should work?

The latest rspec (1.1.4) and the current HEAD
(git:// and
git:// both support Rails 1.2.6.
I think ZenTest-3.10.0 will work w/ Rails 1.2.6 too, and I know it
works w/ the recent rspec.