I have written a few IQ tests. I wrote one in standard 4, and I never found out what my results were.
My parents also had me tested when I was 6, by a psychologist. I found the report recently, and it showed that I was far stronger verbally than I was non-verbally.
I also wrote a few free internet tests, which produced absurdly high results, but I took those with a pinch of salt.
Earlier this year, I was interviewed for a position at a software development company. I thought I had the job in the bag (I aced the interviews with the company). I was then sent to a psychologist for assessments. The personality assessments were fine, but I totally screwed up the intelligence tests. I didn't get the job.
Unfortunately, I can't get the results unless I pay the shrink, something I won't do (a bit of a rip-off, and dubious ethically IMHO). I do have a vague idea of which sections of the test I screwed up on -the stuff about completing patterns and sequences (I was tired when I took the test, as I had come back from a holiday the day before, but I doubt that my tiredness accounts fully for my poor performance on the test).
I did a few IQ-type tests for potential employers after that, as well as skills-based assessments and personality tests, and I have resolved that, if I decide to go job hunting again, I will refuse to take anything resembling an IQ test.
I don't mind personality assessments, and tests that measure specific skills, but I fail to see how figuring out what shape comes next in a sequence would make one a better developer (I think the situation is more complex than all that). (See also this.)
I avoided writing about the topic which I was job-hunting, because it might have seemed like a case of sour grapes, but since I now have a great job, I thought I'd raise the topic. (One of the things that may have landed me my job was this blog. It showed I was savvy enough to pull together a website and that I was relatively clued up on the world around me. The blog certainly didn't hurt my chances.)
The validity of Intelligence tests (euphemistically called "learning ability tests" by some companies) is debatable. Especially since such tests, including "culture-fair tests" are often accused of culture bias. Indeed, the inferior performance of some population groups on intelligence tests has provided fodder for a generation of racists., despite other explanations for these differences.
I haven't done much research into the topic, but I think that the validity of intelligence testing for employment purposes, particularly in South Africa, needs to be examined.