Ehhhh, I say a better test would be to try to live for God... And he will use what he see's fit... For instance recently I think God is using me for a more evangelistic approach to atheists and mormons at the moment which would be teaching and evangelism...
Where as earlier around a few months ago he was using me as more of a healer, for a few people who were growing tired in their walk...
I don't entirely disagree with sites like that, and I think for some people they can pinpoint their 'gift'... But those mire briggs type of gift tests are really geared more to reasurance then anything else... The reason I say this is because you are most likely going to view your life with the aspects you want. And gear your answers towards the gift you want...I.e. if you want healing more then prophecy you might discount those 8 dreams you have had, and put more weight on you seeing a friend in hurt, which has happened considerably less then the prophetic dreams...
The best tests in my opinion is asking people around you, who are able to see your life in person... And to work for the lord and see if you are gifted with digging holes, or building houses...