Yogi went through the "SAFER" dog evaluation testing that they use on shelter dogs to deem adoptability and he passed all tests.  He was nervous but she was looking for his bite inhibition and even though he was shaking with fear while she was "massaging" him in particular, he never once went to snap.

Thanks Nora for your advice with the questions to ask, etc.  I really like this trainer and she really liked Yogi.  She kept saying that I lucked out adopting him and he was a really good dog.  She said she rarely gets good dogs like him in for testing.  I was worried because he snapped at my friend's daughter but she said that he's just never been around children and I'm right  to use caution, but he's NOT an aggressive dog and in fact she said "I only offer this to certain dogs I see, but I also do dog boarding and I've love to have Yogi stay with me."

So I'm pleased as punch about our session, I went ahead and signed up for the other 4 sessions though because we're going to work at him meeting other dogs (she has a dog she uses for this purpose).  Thanks for your advice on this, Yogi is now getting used to his "gentle leader" which is a challenge but he's also getting ten times the treats as normal so he's coping okay!