Blog: Very Short Blog Posts (21): You Had It Last!

Sometimes testers say to me “My development team (or the support people, or the managers) keeping saying that any bugs in the product are the testers’ fault. ‘It’s obvious that any bug in the product is the tester’s responsibility,’ they say, ‘since the tester had the product last.’ How do I answer them?”

Well, you could say that the product’s problems are the responsibility of the tester because the tester had the product last—and that a successful product was successful because the programmers and the business people did such a good job at preventing bugs. But that would be to explain any failures in the product in one way, and to explain any successes in the product in a completely different way.

The idea that testers are responsible for bugs because “the testers had it last” is something Jerry Weinberg once called the “Hot Potato Theory of Software Development”. This suggests a way around the problem—or at least to highlight how silly the theory is. If you’re a tester, send a message to the developers and the product managers noting that you’ve finished testing, and ask them to take on final look at the product before they decide to ship it. Then they had it last.

Instead, let’s be consistent. Testers don’t put the bugs in, and testers miss some of the bugs because bugs are, by their nature, hidden. Moreover, the bugs are hidden so well that not even the people who put them in could find them. The bugs are hidden by people, and by the consequences of how we choose to do software development.

So let’s all work to prevent the bugs, and to find them more quickly. Let’s talk about problems in development that allow bugs to hide. Let’s all work on testability, so that we can find bugs earlier, and more easily, before the bugs have a chance to hide deeply. And let’s all share responsibility for our failures and our successes.

This post, original published in 2014. got a little update in December 2021.

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5 responses to “Very Short Blog Posts (21): You Had It Last!”

  1. shravan says:

    Everone does mistakes and it is quite natural to correct them very fast.The beauty lies in the wonderful word called”quality” which we all are striving for irrespective of the role.It is time to move beyond and work on more possesive things.The object is to work on quality and let us watch the finest roses grow.

  2. Reading the ‘You had it last!’-argument my mind can’t help but extending the argument beyond its intended use and think: So all bugs found in production are user errors, because the user had the product last!

    Michael replies: Right. And since we found out about it because they complained on the Web, everything comes down to Tim Berners-Lee and Vinton Cerf. Damn them!

  3. shravan says:

    Hello Michael sir,

    Iam shravan and from subcontinent.I would like to bring this internet tree to one more level.Web doesnot end with mr Tim or mr Vinton .They were just one among many .The venture capital was given by atlantic and cross atlantic defence research organisation for the purpose of advance communication technology.Some how the new insights are driven to consumer market.There are many economic implications associated with this applications.There are certain merits and demerits.There are various demerits ,for instance all the business models associated with internet giants are flawed and it shoots customers bill.Are we all not leaving for our daily livelihood.There are praise worthy merits linked with this internet in the areas of telemedicine,space exploration ,weather forecasting on the other hand.

  4. Aabharan says:

    I was looking for something like this which is related to testing to development…I found it quiet interesting, hopefully you will keep posting such blogs.

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