no its already been ruled the mmj patients have no protection when it comes to a drug test.. its illegal on a federal level so until that changes you can lose your job
"A California Supreme Court decision Thursday allowing employers to fire workers for using medical marijuana..."
"The company, Ragingwire Inc., successfully argued it rightfully fired Ross because all marijuana is illegal under federal law, which does not recognize medical marijuana laws in California and 11 other states. "
Then again, this was in January of 2008, during the Bush administration, well before Obama's recent changes regarding MMJ. Maybe it's possible in a new case/ruling the outcome will be different.