[vkou]

It depends on whether or not there was a reasonable expectation that the test was going to result in a failure.

Suppose you bought a used car, and the brakes failed before you could drive it off the dealer's lot. The dealer graciously fixes the problem, and points out the great news - that nothing catastrophic happened, and that the problem is now fixed!

You would, of course, start wondering - what other unexpected failures are going to take place, after you drive out of the dealership. Maybe nothing. Maybe something life-threatening.

If the failure was a surprise for everyone involved, I'd be worried - because other surprises might not get caught in testing. If it was a 'Well, we're not sure what would happen', I'd be less worried.