Shouldn't the purchase of the F/A-22s wait until they have been tested?

http://www.newhousenews.com/archive/wood021204.html
The Air Force has spent $32 billion on its new F-22 supersonic stealth
fighter. Twenty aircraft have come off the production line and
hundreds more are planned.
....
But rigorous, independent field testing -- to find out if the F-22
actually works -- hasn't yet begun.

So why not pause production for a few years until the testing is
complete?

-HJC