Check what other systems allow

I’ve been in the process of switching my broadband provider this morning. When I filled in my new providers submission form I was asked for my Twitter username, (@rob_lambert) so that they could get in touch with me whilst the broadband was being set up. Great, I thought.


The only problem was that the submission form would not allow anything that was not an alpha-numeric character as the Twitter username. As you can see, my Twitter username has a “_” in it. Oh dear. The form wouldn’t let me save with my very own twitter username.


When using/integrating with another system (in this instance, Twitter) it is absolutely crucial that you do your homework.

If Twitter allows non alpha-numeric characters then so should you. It is basic stuff. Whatever I can enter in X system, I should be able to enter in Y system. Test Number 1 in my testing book.

In fact, a good place to start would be to create a user on Twitter and see what they allow, and then check the same in your system. Or if you want to dig deeper –


Mistakes like these are very common. Sure, time pressures, lack of documentation, bad design, yada yada are all good excuses, but poor reasons. Twitter is free after all. A little bit of exploration and you could probably map out the valid/invalid boundaries and recreate the same checks for your system…….Compare and contrast. It’s a powerful test idea.