Modals

Cuprite supports Capybara's modal API for alert, confirm and prompt:

accept_alert { click_button "Show alert" }
accept_confirm("Are you sure?") { click_button "Delete" }
dismiss_confirm { click_button "Delete" }
accept_prompt(with: "Linus") { click_button "Ask name" }
dismiss_prompt { click_button "Ask name" }

Unhandled modals

A JavaScript dialog opened without being wrapped in one of the methods above is always accepted. By default Cuprite prints a warning. With raise_on_unhandled_modal: true it raises Capybara::Cuprite::UnhandledModalError instead:

Capybara::Cuprite::Driver.new(app, raise_on_unhandled_modal: true)

The error is raised on the next command sent to the browser. In practice that's almost always the same action that triggered the dialog (a click, visit, evaluate_script, ...), since a JavaScript dialog blocks the page until it's answered. A dialog fired with nothing in flight, e.g. by a JavaScript timer, surfaces on whatever command runs next.