I replaced an O2 sensor on my 96 Explorer and didn't wait long enough to go to get it inspected. Catalyst, both O2 sensors, something else (can't remember) reported "not ready."

I got the instructions for how to do "drive cycles" to get everything back to "ready" status. But how can I check for sure that it's "ready" before I go back to the inspection station? I get a 15 day window for a free re-test, but I think I only get one before having to pay again.