Surely a good quality tester, good with gifted kids, should draw him out. An iq test is not about demonstrating reading or math etc, at that age it can very much be presented as "games and brain teasers". Achievement testing may be trickier. You do read about kids on here who find testing very stressful, or refuse, but they seem most often to be kids with anxiety or behavior issues already known about. My HG+ kid didn't give the first tester she was tested by her best performance, because she didn't like her and would try to give one word or short phrase answers and flat out refused to work for more than half the available time on the coding. She still had a FSIQ in the HG range. The second tester (gifted specialist) noted that she thought DD was sleepy or unwell at first, and then the tester realized she was being observed/tested by DD and she clearly passed better than the first tester, DD warmed up, and was much more interactive (and picked up half an SD, putting her FSIQ into DYS territory). The thing is that both times DD was clearly having more fun than she'd had in ages, even with the first tester she came out positively buzzed - despite her contrary behavior for some of the test. My point being, tester can matter, but working through challenges that aren't necessarily academic work can be really fun for a bright kid.
