Understood. I think that if one wants to predict success / happiness later in life the test should be as much like real-life experiences as possible.

A carefully crafted test-taking strategy is an optimization that seeks to maximize the score. Scoring on the aforementioned test basically wasn't correlated with future outcomes in a significant way, ie it could contribute but isn't a major, main or significant factor in determining how happy or successful people who took it came out.

Retaking tests has these problems, in that people adapt to optimize the result. For example if you told people the result of this test before taking it, I would say you would end up with a lot more people "answering" in the fastest way possible all of the questions. This would destroy the effect measured, in the same way that telling people tests will be ranked by scores erodes the metric.