Not passing smog. Obd catalyst,obd evap,oxy sensor,oxy snsr heat/ test rejection

No check engine light, only thing that pops up on cluster panel is "tighten fuel cap" vehicle inspection report says those 4 test parameters not completed. Mechanic said he had chevy truck recently in for smogging and the guy had to drive almost 500 miles before all the parameters set. What should I ask him today to better provide you with info?