Do you have a Labrador/Terrier mix? How is he with cats?

My boyfriend and I have been looking for a dog and we found an adorable 1 year old Lab/terrier mix at a shelter. He was a stray, but he's had all his shots and vaccines and the man I talked to said he has a really nice demeanor. I have a 12 year old cat that was about 8 months old when I brought him home where we had a 1 and a half year old dog. He is a really friendly cat and loves attention and loves making friends. My boyfriend and I brought Kita the dog over and it had been the first time in 4 months he's seen Kita and he rubbed against her like long lost friends. He would rub against her even if she was eating and she wouldn't make a single noise or negative gesture towards him. Sometimes she would even stop eating because he wanted a taste. I think he would know if the dog posed any threat, but I worry about my cat being stressed. He is a really laid back animal and even long car rides don't bother him too much, but I don't want to bring an aggressor into HIS home. I was just wondering if anyone had any experience with a dog like this. Any information would be fantastic!