Many of the standard tests show basic issues... anxiety, attachment, depression and stuff like that.
Poetrylover, please remember that the test results do not MAKE you those dx's. You are already suffering with "stuff" and they will only help the therapists know HOW and WHAT you are suffering! Nothing has changed within you, and you're needs. Plus, you are not your DX!
Testing will save the therapists time in sessions (and you of course too!) Some tests will help them to know if you need certain medications that can help you feel better sooner, too!
Some of the tests might show IQ. You already have this, too, btw!

But knowing about having certain IQs (low, mid, high) can help you learn to compensate better.
You are still the wonderful "you!"

testing doesn't change that!