Random vs. scheduled drug tests for probation

hello all, i am currently in court for intent to deliver 15 grams. i know im going to be put on probation most likely for 2 years. i was just wondering what determines if the drug tests will be random or scheduled. if theyre random the next 2 years of my life are going to be hell.

im 19 from chicago, it happened in mcdonough county illinois though, where i was at college. damn once a week for 6 months sounds shitty