the engineering team are usually great at writing tests that test their code, a good QA can test alongside them to find cases they've missed and issues that automated code tests can't find. The QA person doesn't have to spend time checking that the app basically works, they can be confident in that and spend their time testing for other 'qualities'
But yes, I've known QA teams that will only find bugs that no one cares about or are never likely to happen - often because they are not trained on the product to be able to dig deep
It seems so obvious to me that your typical engineer, who spent hours / days / whatever working on a feature, is never going to test the edge cases that they didn’t conceive of during implementation. And if they didn’t think of it, I bet they’re not handling it correctly.
Sometimes that’ll get caught in code review, if your reviewer is thinking about the implementation.
I’ve worked in payroll and finance software. I don’t like it when users are the ones finding the bugs for us.
I started off as a dev, wanted to change to being a tester/QA but was told by the CEO that "the customers are better at finding bugs than we are so just give the app a quick look over and ship it out" - I left soon after that.
