I had similar problems after a battery change, I had a lot of frustration at first like you, the testing station said I had to get the computer reset in a week or they would charge me the fee again.
Finally I drove the car for about 20 miles using country roads and suburban roads where the speed was a constant 50 mph for a total of ten miles and 30 mph for the rest of the time with stop snd go conditions. I returned on the freeway at 60 mph for about 10 miles and then mixed 50 and 30 mph speeds back to home.
I think the freeway miles with the other speeds in the one run did the trick as I had previously done the same speeds on separate trips. My OBD reader said I was good to go and the test went smoothly.