I'd be comfortable with Long. I'm a believer. I think a lot of people are selling him short. He's actually an excellent case study - most freshmen shouldn't see live game action at quarterback. They just aren't ready. We saw glimpses of what he could be last season, and we saw how much he struggled. Even if Dungey is way, way better, he's at the very same real risks Long was exposed to. What's he really learning by coming in when outcomes are pretty much decided just to hand the ball off.
Glad you asked this question about what it means to be game tested. Long played in real games, with outcomes in doubt, and lead his team to a road win. Along the way he threw 165 passes, completed 89 for nearly 1000 yards, and had 6 total TDs between passing and rushing.
Some consider what he did to be dubious in terms of speaking to his game readiness.
On the other hand, we have some posters suggesting that Dungey playing mop up duty as a glorified hand off expert for the running backs gets him "game ready" for next season.
Hmm.