Someone I know (not me, I swear!) was excited to interview an experienced candidate with a fantastic résumé for a test lead position.

Said candidate did not know what a unit test was and could not figure out how to write one, even after the concept was explained.

I have no idea how this could ever happen.

Were they a manual tester? HR/Recruiters don't seem to know the difference.

Should they know about unit tests though? That's a developers job.

I didn't interview said candidate but I am under the impression that web-based integration tests were their specialty. Still no excuse to not at least be familiar with the concept of unit tests.