This might not be the right term for it, but it’s the one I use anyway.
Once my draft and primary edits are completed, I like to have 4-5 people who I trust read the book cover to cover, and give me their impressions. I actually wrote up about ten questions for Fugue in C Minor, and the beta readers answered those based on how they felt the book reached them.
It’s very useful to have beta readers who already read the type of novel you’ve written. But it’s also great to have an English teacher or professor as a beta reader. I got a lot of great feedback from the beta testing, so I highly recommend it.
Thing is, self-publishing doesn’t require any kind of quality control or market research. As long as what you write is original, you can self-publish anything.
But I think it’s best to do as much quality control as you can.