Those little empty cases are not "test fires" as in "Oh look, your new firearm works. See, here's proof."
Those are included for ballistic fingerprinting. Some states require it. In those states I suppose one (maybe both) goes somewhere, where they are stored in some warehouse, like the Ark of the Covenant in Indiana Jones, but they're on file "somewhere." In other places like around here, they usually are ignored, or tossed into the trash/reloading box.
Who does it? Any company that wants to do business in those states that require it. Since they don't know which guns are going to go where, they simply do it to all of them.
If you got targets, consider it a bonus. I've bought a lot of guns from a lot of different manufacturers, and I've never seen one.