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 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?