Skills aside, how fit would you say someone has to be to enter the ring at amateur level? (I mean in terms of sort of 'tests' you could do to determine fitness.)

i can't really tell you any tests but what i can tell you is that, if you've got a good trainer and you trust him he'll know when you're ready or not. even though this may be more about skill, here's a for instance; he's got guys that he's been training for six, seven, eight months who he still doesn't feel are ready. if you can make it through your roadwork and don't pass out/have headaches every day after training and can make it through four rounds of sparring, you're physically ready.

can't really tell you any tests but what i can tell you is that, if you've got a good trainer and you trust him he'll know when you're ready or not.

QFT

Having a trainer that you trust is a must.

What does QFT mean?

The short answer is when you are fit enough to spar and hold your own.

dosent matter if your fit enough, youve got to be able to score points and land shots comfteraly against a good level of oponent, ive been training 2 years, and shoud have fight soon,