nerd

I’ve been writing Selenium tests lately. It’s not fun, but it’s helped uncover a few bugs in our app. There are a number of places where Selenium doesn’t shine: its CSS selector engine doesn’t always find the node I’m looking for, server-based tests have a relatively anemic API, and it doesn’t support native drag & drop.

I don’t really agree with PPK’s assessment of HTML5’s drag & drop API: it’s messy, but not impossible. I added support for HTML5 Drag & Drop to the Dashcode/Coherent library with little or no pain; I also added fallback support for Firefox 3.

By manually disabling the support for native drag & drop, all my Selenium tests pass, but that’s not really a scalable solution. So I really needed to find some way to detect that I’m running within the Selenium test harness. Unfortunately, the library installs event handlers immediately, so I need to be able to detect whether Selenium is running before it injects it’s alert handler (which creates the detectable window.seleniumAlert function).

The only thing I’ve found is that Selenium creates my window with the name selenium_main_window or something similar to that. Therefore, I’ve added the following to the Browser flags for Dashcode/Coherent:

SeleniumActive: (-1!==window.name.indexOf('selenium'))

And then in the Support flags I have:

/** Determine whether the browser supports Drag & Drop properly. Mozilla
    prior to 3.5 doesn't work correctly. When running under Selenium, native
    drag and drop is disabled.
 */
DragAndDrop: !coherent.Browser.SeleniumActive &&
             ((coherent.Browser.Safari && !coherent.Browser.MobileSafari) ||
               coherent.Browser.IE ||
              (coherent.Browser.Mozilla && !!window.localStorage))

Of course, this will completely fail if the window is opened via another method, but it’s the best I could do.