For certain, this is the best way to do testing's IMHO. I never want a student to feel like it is slam dunk, instead I want them going into it as confident as possible. Of course, people are people so that is all over the spectrum. It is a great feeling as the instructor to see a person do more than they thought they could.Way back I've had rather "easy" tests where one just had to know the material. I've also had really, really rough ones. I've never been a "real confident" type and always felt "unworthy". Not a good way prosper maybe, but it is what it is. I always relied on my instructors and superiors opinion yet still have on occasion questioned their decisions.
As an instructor we definitely leaned toward pretty tough testing. I have heard black belt tests I've given sometimes referred to as "brutal". But I survived a few myself and figured anyone else can too. There were always other black belt examiners included and we would confer. I don't think I ever failed anyone testing for black belt. In fact I never let anyone test unless I already considered him/her a black belt already. A couple of times I did have to pause a test for "private counseling" when it appeared the student was "in turmoil". The counseling was done by another black and never by me. In both instances it worked wonders. I never tested to check if the student had the knowledge and skill but always to find how badly they wanted to join the black belt level.
The idea of testing someone for black belt and failing them is anathema to me. In my dojo I had the last say and never farmed the decision out to someone who didn't know me and my dojo.
This post makes me think of my 3rd Dan testing. Absolutely grueling 5-hour ordeal. It was about a year after my Olympic run and I was in very good shape. And my GM squeezed every ounce of 'shape' out of me.
Great memories.