Testing for Brown M&Ms

One thing I’ve learned in my testing career is that where there are bugs, there are more bugs. Some of my colleague Nachi’s research shows that components with a high number of pre-release bugs has a corresponding share of the post-release bugs. The heuristic works well on a smaller scale too – if I find annoyances or other slop 10 minutes into a testing session, odds are that there are many, many more bugs in the feature.

This post by Ajay demonstrates a good example of “slop”. There are certain things anyone designing a kiosk application should do to ensure that the application remains in kiosk mode (sidenote: as a tester, I love kiosk machines because they’re a great target to demonstrate testing ideas). When I see flaws like this, I know there are more – perhaps dozens or even hundreds of other flaws in the application, and I wonder how many of those flaws are exploitable for more serious damage.

And now, as I read the comments, I see that JB said basically the same thing in the first comment.

And then I was reminded of this article I read last week about business advice from Van Halen. Van Halen were famous for the rider in their contract stating that they should have a bowl of M&Ms with all of the brown candies removed. It seems like an arrogant rock star tactic, but there was something significant in the request.David Lee Roth knew that if the M&M request wasn’t handled correctly that there were likely other problems in the venue adhering to the contract. Brown M&Ms in the bowl indicated that a deeper look at the logistics of the event were in order.

In other words, Roth was no diva. He was an operations expert. He couldn’t spend hours every night checking the amperage of each socket. He needed a way to assess quickly whether the stagehands at each venue were paying attention — whether they had read every word of the contract and taken it seriously. In Roth’s world, a brown M&M was the canary in the coal mine.

I’m sure there are hundreds of examples of the “brown M&M heuristic” – now I just have to see if I can remember to call it that.


*I have no idea why I decided to use the word “slop” today to describe annoying behavior, so don’t ask.


  1. Ha – the very first presentation I did at my current company was all about Van Halen and brown M&M’s and people still remember it. Good to see it is still going


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