Green Card=Drug Test???

Ok guys im in the process of getting my green card and i know theres an examination involved as in a physical, i know they drug test(What Happens if I Test Positive for HIV?) but i also want to know more info, so if anybody has been through this or knows anything about it please say something, like does anyone know if its a urine test or a blood test? Which one should i be hoping for?
Thanks in advance for taking a look

why not just stop smoking for like 1 month and burn fat by running before getting your green card? Then you'll have no worries.

Oh yea i quit (let me refraise that, i went on break) as soon as i found out, that was almost 2 weeks ago, but im worried if they test my blood that they can trace it back to 6 months, and also i just scored some crip thats really tempting me