Integration tests involving Javascript dialog boxes

I’m working on an integration test for a project that uses minitest and
Capybara. You can find the source code in question at
https://github.com/jhsu802701/ruby_mn_site/blob/sponsors_delete/test/integration/sponsors_change_test.rb
in
the section ‘super admin can add, change, or delete sponsors’.

When you click on the Delete button, there’s a Javascript dialog box
that
asks if you’re sure and gives you the “Cancel” or “OK” options. How do
I
get the test to click the “OK” option given that the normal
Capybara/minitest commands only work on the HTML page and do not work on
these pop-up dialog boxes?