Please do also tell what's influenced the accuracy or reliability of your test results, as well.
For me, here's my list tests, in order of most to least reliable:
#1 - most reliable test I've done, consistent results from year to year, and also meaningful: DISC
#2 - Hermann Brain Dominance Index
#3 IQ tests - I've got bimodal distribution in this. The higher result, when I have got it, has stayed very accurate over almost 15 years with little variation. I've got the lower score in my years of burnout, depression and recovery from it. I'd say this is accurate, with reservations. IQ can be stable during person's life as a theoretical concept, but in reality, person can have downs.
#4 (bunch of all kinds of tests)
#5 MBTI .. test scores are all over. There is some center in tests scores in the last few years, with little more consistency lately. If I'd really stretch my belief, I could believe this thing to be reliable for me in the future.
#6 Enneagram. Test scores vary so greatly there is absolutely no point for me to consider this typing system. There is only one very slight chance that one type might be a decent fit for me. No, this test has failed for me as a reliable psychometric instrument.