There are quite a few places that do PAT testing (or ISITEE to give it is correct title these days) at fairly reasonable prices, far cheaper than you could do yourself unless you plan on doing a lot per year. If you have a batch of a few to be tested it would be cheaper as a lot.
You probably could and should do a basic "does it seem to work?" test first to rule out ones that are not functional, but the cost of a tester, course, and insurance to cover your posterior for anything that might go wrong, makes it not worth doing yourself unless you are doing, say, a hundred per year or more.
Of course, if you do have need for many items or other electrical stuff being tested then you might find it cheaper to go on a 1-2 day course, buy a tester and get basic insurance for it.
You probably could and should do a basic "does it seem to work?" test first to rule out ones that are not functional, but the cost of a tester, course, and insurance to cover your posterior for anything that might go wrong, makes it not worth doing yourself unless you are doing, say, a hundred per year or more.
Of course, if you do have need for many items or other electrical stuff being tested then you might find it cheaper to go on a 1-2 day course, buy a tester and get basic insurance for it.