Massachusetts drug testing

So I'm wondering if they can test for cannabis now that its legal for medical use in MA. If you test positive do you have to show a script or your card or something? Just wondering because I'm in the market for a job and I'm wondering if I should broaden my search to include jobs that drug test haha.

Any job can deny you no matter if you have a card or not.. The drug is still illegal in the fed government and ultimately that's who stores answer too..also they have the right to building a drug free work place

Chances are good that if you test positive for any of 'popular' drugs, you'll never hear from them again. They're not going to call you & ask if you have a script, they'll just move on to the next guy/gal.