Drug Test for SA roles

Looking for some insight on the drug test policies and timing at various banks in NY for SA roles. I just had a superday and wanted to smoke some to ease off the stress but now I am worried about getting tested since offers will be out soon. Looking for insight particularly on Citi, BNP Paribas, and RBC. Mainly, do they screen for weed after accepting the offer or once the role starts? Additionally, is the new legislation regarding NYC employers screening for weed affect roles that begin after the law goes into effect? I have already been holding off on smoking for awhile just to prepare for worst case scenario but still would like some more concrete answers from anyone who has gone through the analyst track at these banks. Any insight would be greatly appreciated.