rspec users - Oct 2007 - specs for RJS

What''s the current best practice for spec''ing (and stubbing)
RJS?
response.should have_rjs(*args, &block) from rspec_on_rails works well
for things that
assert_select_rjs supports.  But for other things, like say
page[:elm].add_class_name :class_name, it''s not clear to me the best
way to test for this.

I''d love to be able to do something like
page[:elm].should_receive(:add_class_name).with(:class_name).  Is this
possible to do?

Thanks!  Rspec rocks!

-ben