I found it was most helpful to just be upfront with the PO. The first test probably won't mean much anyway. It doesn't sound like your a big smoker anyway, and maybe got suckered into using your get out of trouble diversion card (usually first time offenders) for something lame like most every one does, so not much of a trouble maker... Kinda wish I saved mine for a real charge, thinking back on it..
They mostly wanna see what happens after the first test, which you don't really get any violations for even if positive, i'm pretty sure...
I was lucky that I had a medical card, and my PO got me a hearing in front of the judge to explain why I should be able to use cannabis while doing my 2 years.. I had my day in court, and actually won for once. I feel like my no BS honesty really helped me to skate through the last time around with court/PO BS, and even got off months early. Stoned af the whole time, and only had to do maybe 1-2 tests, lol. He knew I was telling the truth when I said "heeey my man, yup.. just smoking some weed here and there, you know.."
They sit around listening to people act like victims who try to hide things, and lie about stuff all day long. You'd be surprised how far they might go above and beyond behind the courtroom scenes to make the process go a lot smoother.. when they actually see that someone wants to fix the problem. Trying to fake tests in a probation office that watches you sure isn't helping any situation.. Especially for guys with strap-ons who get caught way easier. Haha