We told our DD (7.5 at the time) that the test was to help see how she learns best and that the questions got harder and harder until almost no one would be able to answer them and the tester knew that (just to keep her from freaking out if she started feeling out of her depth). This was for the WISC-IV.
Rapport is a big deal, but she loved her tester and had a great time with the test. Her lowest score was processing speed (which came in as normal for her age) but it didn't seem to stress her out -- and she'd be likely to get stressed in a high pressure full speed situation as well.
She loved the test and only started to get a little tired at the end (according to the tester, I didn't see or hear any of the testing). The only amusing thing is that questions didn't get too hard on some of the subtests... she ran out of questions instead.
