TDD at interviews

Allan Kelly posted an article on DZone this week predicting that TDD would be a required skill for developers by 2022. Vishal Biyani asked on Twitter about how one might test TDD skills, and I promised to blog about my experience of using Cyber-Dojo in interview situations.

Cyber-Dojo is a browser-based dojo environment developed by Jon Jagger that supports a lot of programming languages and xDD frameworks. It’s great for dojos because it has few of the productivity frills that we’ve come to depend on over the years – no syntax highlighting; no autocompletion; no suggested fixes. That means we have to think about what we’re doing, rather than relying on muscle memory.

As Jon eloquently puts it in the FAQ: “Listen. Stop trying to go faster, start trying to go slower. Don’t think about finishing, think about improving. Think about practising as a team. That’s what cyber-dojo is built for.”

That might be what cyber-dojo was built for, but it turns out that it’s also excellent as an interview environment. Your interviewee writes real code and has to diagnose with real compiler/runtime errors. They’ll have to use a browser to remind themselves of all the basic knowledge that has atrophied during years of nanny-IDE development. And, best of all, there’s no save, build or run functionality provided by cyber-dojo. There’s only a single button and it’s labelled nice and clear: TEST.

Use one of the katas whose instructions have been helpfully included with cyber-dojo, or roll one of your own, and see how your interviewee responds. Every time they press the TEST button, all the code they’ve written is sent over to the server to be built & run and the response is returned, along with a traffic light: green for “all tests passed”, red for […]

By |January 11th, 2014|Practices, TDD, Unit testing|1 Comment