If you get a "Scangauge II" OBDII reader, it will show status of codes and tests, and say when "READY" or "Not READY" to pass tests. If it is not ready, you can input a code and look up the results and see which test is not complete yet.
The 02 tests, and the evap tests can take several warm up driving cycles to complete, typically more than 1 day.
On my 2002 T&C Van, the instant I noticed a "READY" on the display, I drove straight to an inspection station. It passed, then the light came back on the next day! (It was cracked vacuum hoses under the van for the evap system. I wish people would quit with the "Its the gas cap" crap)