Pass to Fail, Fail to Pass Heuristic Rikard Edgren

When teaching scripted testing (yes, I actually do this!) I found the Pass to Fail, Fail to Pass heuristic (used by many, but now with a catchy name.)

The essence is that when a not-overly-simple test has resulted in a Pass, think about it some more, and try to make it Fail instead.
When a not-overly-simple test Fails, think about it some more, and try to make it Pass.
This will stop you from jumping to conclusions; you will find out if the essence of the test case was Pass or Fail; and you might have isolated a bug or two in the process.

Example: Test case is about resizing 200 images at once. The essence of the test (many images) actually works, but some testers might report a Fail, besause it didn’t work (but the reason was that (at least) one of the images wasn’t handled properly.) When Pass is reported, you might have missed a chance to run a complex test that could find important problems.

This is a specific instance of the generic Do Variations Heuristic (Creep and Leap is another instance) As with all heuristics, it is to be used with judgment.

QA Tester August 31st, 2013

Good post!! The point you have mentioned in interesting, good way to learn more while testing and this experience will be useful further when working on a huge projects…

I liked it. Thanks for sharing.

Rikard Edgren September 6th, 2013

I am not sure if this is more or less useful on huge projects, can you expand on that?