Ewww, no. The programmer should have run their unit tests, maybe even told you about them. You should be testing for edge cases not covered by the unit tests at a minimum and replicating the unit tests if they don't appear to be very thorough.

[–] mspencer712@programming.dev 7 points 2 days ago

This.

My units and integration tests are for the things I thought of, and more importantly, don’t want to accidentally break in the future. I will be monumentally stupid a year from now and try to destroy something because I forgot it existed.

Testers get in there and play, be creative, be evil, and they discuss what they find. Is this a problem? Do we want to get out in front of it before the customer finds it? They aren’t the red team, they aren’t the enemy. We sharpen each other. And we need each other.

[–] nogooduser@lemmy.world 2 points 2 days ago

I think that the main difference is that developers tend to test for success (i.e. does it work as defined) and that testers should also test that it doesn’t fail when a user gets hold of it.