Don't forget that natural fluctuations in a human body can influence whether one has low, normal or high levels of testosterone. Another thing to consider is how long you have been on hormones. It usually takes quite a bit of time for all the testosterone to leave your body or at least get to a female level. My guess is it shouldn't be an issue, although they may ask what medications you are one.
As for having drug testing done, I can give you my take on this as I have been on the employer end of this. Typically this is performed by another company and all they will test for whatever you pay them to test for (usually drugs only) and they will just tell you whether it was a positive or negative result. So if they do know you're on HRT, it's unlikely they would disclose it.
Melissa