Made lots of attempts at getting Selenium to respond to the alert dialogs. There is clj-webdriver taxi support for alerts now but the PhantomJS driver doesn't support them.
I tried switching over to Firefox which is also supported on Travis-CI but Firefox supports HTML5 so it never gets to the popup as the browser's client-side validation fails before the ClojureScript validation.
I then went down a wormhole trying to validate that the browser's client-side validation failed, which I figured out. Key was that there is a known issue with Firefox 23 and Selenium's executeScript (solved by downgrading to Firefox 22), there is a validity property on the element, and execute-script requires an explicit return in the provided JavaScript to return the validity element or portions thereof.
It's unclear the right direction to go from here. Do perfunctory testing of the validation with PhantomJS and leave it at that, moving on to testing that the contents of the page have been customized properly? Or push on with browser testing of validation, maybe even figuring out how I can regression test on other browsers.
Definitely hitting diminishing returns with this project becoming overly tested. But a key goal is learning about testing with Clojure which is still happening.