Depending how old your vehicle is, the catalyst monitor might be allowed to remain incomplete and the vehicle still pass the smog inspection. Currently 1999 and older gasoline powered vehicle's are allowed one incomplete monitor. This can be any monitor, including the catalytic converter (catalyst) monitor if the check engine light was not recently illuminated due to a misfire detection AND you did not undergo and fail a smog inspection because of it.
For all 2000 and newer gasoline powered vehicles, one monitor is still allowed incomplete however this must must be the EVAP monitor. All other monitors have to be ready or completed.
Diesel vehicles have a different set of emission monitor rules which I've linked to here.
