When test automation is nothing more than turdpolishing

By Jim Grey (about)

I used to think that writing a fat suite of automated regression tests was the way to hold the line on software quality release over release. But after 12 years of pursuing that goal at various companies, I’ve given up. It was always doomed to fail.

In part, it’s because I’ve always had to automate tests through a UI. When I did straight record-and-playback automation, the tests were enormously fragile. Even when I designed the tests as reusable modules, and even when I worked with a keyword-driven framework, the tests were still pretty fragile. My automation teams always ended up spending more time maintaining the test suite than building new tests. It’s tedious and expensive to keep UI-level test automation running.

http://xkcd.com/844/
http://xkcd.com/844/

But the bigger reason is that I’ve made a fundamental shift in how I think about software quality. Namely, you can’t test in quality – you have to build it in. Once code reaches the test team, it’s garbage in, garbage out. The test team can’t polish a turd.

Writing an enormous pile of automated tests through the UI? Turdpolishing.

I’ve worked in some places where turdpolishing was the best that could be done. Company leadership couldn’t bear the thought of spending the time and money necessary to pay down years of technical debt, and hoped that building out a big pile of automated tests would hold the line on quality well enough. I’ve led the effort at a couple companies to do just that. We never developed the breadth and depth of coverage necessary to prevent every critical bug from reaching customers, but the automation did find some bugs and that made company leadership feel better. So I guess the automation had some value.

But if you want to deliver real value, you have to improve the quality of the code that reaches your test team. Even if the software you’re building is sitting on a mountain of technical debt, better new code can be delivered to the test team starting today. I’m a big believer in unit testing. If your software development team writes meaningful unit tests for all new code that cover 60, 70, 80 percent of the code, you will see initial code quality skyrocket. Other practices such as continuous integration, pair programming, test-driven development, and even good old code reviews can really help, too.

But whatever you do, don’t expect your software test team to be a magic filter through which working software passes. You will always be disappointed.

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