If a is person being tested is injured during a post offer testing evaluation, is this a worker's comp. injury for the employer?

I agree with you Raymond

In my experience, the conditional hire would fall under WC if injured during the employment process, as the evaluator may be considered an extension of the company. But the truth of the matter is that any injury occurring during post-offer testing would more likely be compensated through the evaluator's malpractice or liability insurance and all expense incurred by the employer's WC provider would be recouped upon settlement. 

Of course, every employer works differently and all decisions will ultimately be determined by the attorneys. Hope this helps.

If i understand the question correctly , you mean the person did a test in order to declare him competent in a field. If this is the case, then yes. This has happended to me. The law sees it as such - the person is working under your supervision, thus according to the OSH act, your are responsible for his safety and health been. In order for you to comply to the act, you need to prove compentency by doing training, thus employing this person temporary or permanently to do this. It you can prove neglegentcy on his behalf then his injury is on his own and maybe liable for further actions against him in the labour court. This been said, if you cant prove neglegentcy on his behalf then the company bears the resposibility and the person is in line for worker's comp.