From the book (pdf) p.165, the code snippet in test/controllers/line_items_controller_test.rb:
assert_select_jquery :html, '#cart' do assert_select 'tr#current_item td', /Programming Ruby 1.9/ end
No JQuery call matches [:html, "#cart"]
According to what I’ve googled, it has something to do with jquery-rails. However, the issue seems exists for a long time. (https://github.com/rails/jquery-rails/issues/188)
I wonder why it’s not fixed.