I wouldn't say your risk is non-existent, but extremely, and I emphasize extremely, improbable.
There are several factors making transmission unlikely. First off is that the retrovirus, if it behaves like others, will exhibit periods of dormancy when it cannot infect. In addition there is usually a co-factor, meaning a slightly compromised immune system in the recipient. Thirdly, it would be more likely if there was blood in the mouth of the person who was HIV positive. HIV is pretty hard to transmit.
In any event, getting tested immediately is pointless. The retrovirus takes at least six weeks to seroconvert.
What is a problem with those who are HIV positive is that many (certainly not all) carry hepatitis, as well as tb.
Your risk is non-existent. I wouldn't worry.
Placebo effect. If you're really concerned see a doctor.
you don't have HIV...you can't get it unless you have sex with/get a blood transfusion from/share dirty needles with an HIV/AIDS positive person...it's possible to get it from saliva but in order for that to happen,you would have to drink a gallon of their spit...no reason to get tested for THIS but if you're sexually active,you should get tested anyway