Earlier quoted context omitted.
IQ test is bullshit and has been debunked a number of times. Nowadays anyone bragging about their IQ should be considered a moron and left talking to themselves. For example: https://www.youtube.com/watch?v=W3oUqKUx2o0 (first thing that came off my head)
a test in isolation cannot be bullshit. when people talk about iq test many people imagine the person believes an iq test is a rigorous measure of all intellectual talent. or course it is not that. but it is also wrong to suggest it has no meaning at all. it does have some predictive power. imperfect measures are not always useless, which is goof since all measures have some error.
A test trying to measure something we can't even properly define is kinda flawed in it's whole premise.
As such the best an IQ test can do is measure how well somebody prepared for a test like that, but it will struggle to properly catch any knowledge or skill domains not covered by the test, of which there are a lot.