Negative testing is something I’ve done as long as I’ve been in QA, but isn’t a term I was familiar with – so I never actually classified the negative testing I was doing as anything other than testing. I heard the term used for the first time at my most current job; a recent interviewee was asked to negatively test a water bottle, which had us all stumped for a bit.

Negative testing is how you test your application for how it handles exceptions and errors. So, negative tests are testing the one-offs, the invalid inputs, etc. On our Facebook login test this would be trying to use an invalid email address to sign in – we should then get an error/prompt informing us of such.

In negative testing getting error messages is expected, and is part of what you’re trying to verify – how errors are being handled, and verifying they are being handled correctly, as well as to ensure performance stays where it should be and your application doesn’t crash.

Graceful, and proper error handling is so important for the customer experience, so negative testing is honestly one of my favorite ways to test. You know when you see the endless spinner, but actually something happened in the backend and you have no clue, and are just waiting forever? That’s what negative testing helps prevent – instead you’d get some sort of error telling you there was an issue. I know I’ve wasted plenty of time trying again and again to load a page, or make a payment, when I keep getting an endless spinner but really I’m getting an error that no one has accounted for with error handling.