I feel your pain! I am HORRIBLE at taking tests, but have been an SEO writer for 13 years with no negative reviews from clients/employers. Tests are no indication of your knowledge, just how well you can concentrate under pressure (if the test is timed).
I see that you can make the test results private, BUT I am wondering IF the algorithms are programmed to promote higher scoring people...Hmmm.... I am wondering if IT or the engineers at Fiverr have it set up that way....