I was part of a team doing acceptance testing of the new instances company installed for the clients. What we needed to do, in general and most broad terms, was that every system / feature most important for our clients is their and does a few things.
While OS or SQL server is not like that, I think the main goal is more or less the same: if you customers want to have some important features / system tested, you may do that with some, say, checklist.
Like, say, for a new OS installation
- Boot system
- Login
- Connect to Wi-Fi and/or ethernet (whatever is to be used)
- Check that sound works
- Install some basic software from the list
- Run the basic software from the list
- …