How can you tell if a turbo is bad

I just took apart my old turbo assembly (working first turbo, broken second turbo) and i was examining the two turboes and i can't tell which one is good and which one is bad. Is there any way to determine if a turbo is still good by simple inspection?

This is why i need to know:

My dad accidentally broke the shaft off the first turbo (which was working) because he turned a bolt on it left to loosen it, but left tightened it. So what I did is i put the 2nd turboes shaft in the 1st turbo, and stuck the 1st turbo cartridge in the 2nd turboes compressor housing. I'm hoping that will work, however, i was just curious if there was any way i could just inspect it to tell before i put the thing in the car and have to do this whole thing over again. I know it's a very awkward situation, but hopefully someone can help me out. Thanks.