The term “Heisenbug” is a playful pun on the name of Werner Heisenberg, the well-known physicist who first asserted the observer effect of quantum mechanics. “The observer effect (not to be confused with the uncertainty principle) is the fact that observing a situation or phenomenon necessarily changes it. Observer effects are especially prominent in physics where observation and uncertainty are fundamental aspects of modern quantum mechanics. Observer effects are well-known in fields other than physics, such as sociology, psychology, linguistics and computer science.” - The Observer Effect: IEEE publication, K. Baclawski et al. An example would be checking your tyre pressure. By simply attaching a tyre gauge to the valve, you’re almost guaranteed to lose a very small amount of air. So simply by trying to read the tyre pressure, you’ll have changed the tyre pressure. With this in mind, we can assume that the mere process of trying to reproduce a defect could change the behaviour of the code enough that the defect no longer occurs.

Eighteen months, 19 modules, and 59 amazing contributors later, the MoT Software Testing Essentials Certification is complete! Looking back, my favourite part has been seeing so many community m...

You can now earn a Community Star when you start a Club post. Coming soon you will also earn a star when you contribute to a Club post too. I'm also taking this opportunity to thank Simon, J...

Happy times gathering again at MoT London with these quality people.

Bill Matthews is giving a fantastic talk on testing LLM-based applications.

Have a browse of our upcoming community-led meetups

Have a browse of our upcoming community-led meetups

Explore missed bug reflections, discuss internal QA conferences, and uncover the impact of self-taught learning in episode 65 of This Week in Testing!

Reimagine irreproducible "Heisenbugs" as opportunities to strengthen your team's debugging practices

Two people smile for a selfie in a theatre with red seats and decorative walls. One person gives a thumbs up, wearing glasses and a hoodie. The other person wears a cap and has a beard.

A bearded man in a cap and a woman with glasses and long red hair take a selfie indoors. The woman wears a pink jacket and a name tag while flashing a peace sign. People are visible in the backgrou...

It's always great to catch up with the Postman team aka - Danny, Gbadebo and Sterling (aka Mr AI).