Which tests should i run on new hard drives to discard defective ones

[userwords]

Got some drives and also a few seagate backup plus portable 4tb ones among them. I also want to resell some i have. I want to stay sure all drives are defective free as much as i can, before trusting those any data, or selling others. How can you fully scan and then burn in test (to discover any damage that may show only under stress and not in idle) each drive to be sure each one is 100% flawless.
Note the order of each test with each software or tool recommended, incase it is better to do one before the other (like maybe first stress tests then the surface scanning ones, or whatever).

 

[Elixer]

Well, normally, start off with a full erase, then do some kind of butterfly testing with HDDScan (free) usually finds duds pretty quickly. Pay attention to the access times, usually, the higher those are compared to neighbor sectors tells you that sector can be on the way out.
Of course, they can still fail at any time though, no real way to get around that.