I brought my car in for a test and the owner of the station helped me out - he ran the test and my test was "rejected". He explained that this is different than failing and it means that the on-board computer had more than 1 sensor that wasn't "complete". Essentially I hadn't driven the car enough since the engine had been reset (I had taken the battery out to work on the car the previous weekend).
Instead of ringing me up and charging me for the rejected test, he just told me to come back when I had driven the car another 100 or so miles. 3 days later I came back, and he tested my car. Was in and out in less than 4 minutes. $18.99.
Honest, friendly, and efficient. Everything you could ask for in a smog testing facility.