Salvia is legal... why would they test you for it? and on what grounds would the fire you on, since it is legal
But they do test for opiates, since salvia is an opiate it may show up on the test as one, which would mean you'd have some explaining to do. Yes its legal, therefore you wouldn't get into any kind of trouble, plus It only stays in your system for a short period of time. Overall I wouldn't worry about it unless you tripped 3 hours before your test.