Wednesday, December 5, 2012

Not Providing an HTML Page? Think of the Kittens!

Consider the following request for help with Selenium WebDriver:
I'm having trouble getting something working in WebDriver. I'm getting a NoSuchElementException when I try to execute the following code:
What could be causing this exception, and how do I fix it?
Obviously, this code could have several potential problems. The ID attribute of the element may be wrong. The element the user is looking for could be inside a frame or iframe. The element may be added to the page DOM via some JavaScript library, and the browser hasn't had time to process the JavaScript yet when the findElement call is made. Or it could be something else. What's missing from this request for help, whether the request is made in a post to one of the user-facing mailing lists, or in an issue report, is context. Anyone reading the request won't know the structure of the page the user is automating, so any attempt at help is going to be pure speculation.

Most of the time, people wanting to help the requester will respond with something along the lines of, "Hey, we really can't give you any guidance unless we can see a page that reproduces the problem. Can you share the page, or a URL to a page that will demonstrate the issue?" Surprisingly often, this simple request for more context is met with a very large amount of resistance, along with reasons why it isn't possible. Almost equally as often, these reasons are bogus. Let's look at a few of these reasons, and see why they're bogus.

Evans Bogus Reason 1: "It's hosted on an intranet."

Just because a webpage happens to be hosted on an intranet doesn't mean it can't be shared. Yes, it will require some effort on your part to make it public. Such applications usually rely on some sort of database connection, or connection to internal resources, or LDAP integration, or some other such thing. Here's a little secret: Because WebDriver works only on the UI, your WebDriver problem most likely has nothing whatsoever to do with those underlying technologies. Yes, that means you'll probably have to stub out anything like that your application relies on before you can make it public, but it can be done.

Evans Bogus Reason 2: "We're so afraid someone's gonna steal our super-secret site concept/source code"

This reason is often imposed from on high by an upper management drone. It's penny-wise and pound-foolish. You're paying someone good money to develop automated code against your web application. The people you're paying are encountering difficulty to the degree that they need outside help to figure out why. Yet you're so scared that someone is going to steal your precious code or idea that you refuse to let them get help, and causing that money to be wasted because your automators aren't being productive.

I direct this next bit to those short-sighted nincompoops who refuse to get out of their people's way. If you're going to insist on making it hard on your WebDriver coders who are caught between a complex web application and your tunnel-vision, I'll make an offer here and now to sign whatever NDA is required to get them some help; however, I'll charge a fee for it. A big one. Much, much more than if you had just let your coders get the help they need in the first place.

Evans Bogus Reason 3: "Do you know how complicated my site's JS framework/CSS/HTML code is?"

The snarky jerk in me always wants to respond to this reason with something like, "Well, no, I don't know how complicated it is because I can't see your code from here, but it's highly likely that complexity is exactly your problem." Simplify the page down to plain, vanilla HTML if you can. It's not like WebDriver is entirely untested. There's a CI server that runs a bunch of tests (600+ at the time of this writing) on every single commit, against 5 version of IE, 4 versions of Firefox, Chrome, and Opera. If you're doing something reasonably common in your WebDriver code, it's probably a safe bet that it's not going to be globally broken for everybody, everywhere, against every web page.

Also, there's no requirement that someone needs to use the exact same site that's giving them the problem. One that is similar will do the trick, which is why we who try to provide help often say ask for "an HTML page, or a public URL to a page" that demonstrates the problem. Here's a tip, most of the JavaScript UI frameworks provide public demo pages. See if you can replicate the behavior from your WebDriver code against the demo page.


Evans Bogus Reason 4: "But I'm just a lowly tester, and I'm not allowed to touch the application code"

I can't believe this is actually put forth as a reason, since the solutions are many and obvious. Work on a private fork of the application code. Enlist a developer to help you. Try to reproduce your problem against a different, public site.

Remember, We're All Volunteers Here

The people who develop and provide support for WebDriver are unpaid volunteers. If you're having an issue with running WebDriver against your web application, and you need to ask for help why it's failing for you, it'll go a long way toward establishing goodwill (and getting you a productive answer) if you provide everything someone needs to reproduce your problem easily.


  1. Hi Jim,

    thanks a very lot for this article!
    There's ScrapBook out there, useful for easyly extracting the page without breaking the DOM.
    I made some thoughts about the topic yet in the mailinglist:!msg/selenium-users/T2lbH3Nfpto/vH8kfiFCl0MJ
    Maybe we can compile all our thoughts and commit them to the docu.

    Thanks again,
    Yours Michael

  2. The 'lowly tester' problem annoys me. If you are creating some automated tests, you absolutely need access to the underlying source code of the website. You absolutely need to understand how the UI is structured to create effective tests.