http://dev.rubyonrails.org/ticket/8750 will address of the issue of not being able to use:
assert_select_rjs :replace assert_select_rjs :replace_html
when you use:
Currently you have to use :chained_replace and :chained_replace_html in your assert_select_rjs calls which seems unneeded. It also makes assert_select_rjs seem broken to people who use the page[id] syntax over the "page(id, ...)" syntax.
Could someone with commit access please review the ticket,