In the last couple of weeks someone posted the belt size to use after removing the air pump. A pre-test might be a worthwhile gamble before replacing the air pump. If they notice it's missing during a pre-test, it doesn't get reported. You'll have to pay for a real test regardless of pre-test results.

Since I'm neither a lawyer nor mechanic and thus not liable for this suggestion, you might look into a timeshare air pump. Borrow/rent a good one to pass smog and use a shorter belt the other 23.9 months. It doesn't have to work since the CA test is done on a hot engine. It just has to be quiet.

Sixto
95 S420
87 300SDL