SeaTools is a long-standing, trusted tool for HDD testing. I always have a bootable drive with the SeaTools bootable image on me for diagnosing hard drives.
https://www.seagate.com/support/downloads/seatools/seatools-legacy-support/
Keep in mind that testing a failing drive will likely make a failing drive worse. For your use-case this is fine, but for anyone else looking to test drives, please create a backup image of the drive prior to testing.
Maybe you’re pronouncing sewer in thinking of a person who sews instead of sewer as in waste drainage.
They aren’t a junior dev yet. They’re looking for a job as a junior dev and have been unsuccessful at finding a job as a junior dev.