What is Cold Cranking Simulator (CCS)?

According to wikipedia, the cold-cranking simulator (CCS) is designed and made as a method of determining the low temperature performance of lubricants, in the specific condition of "cold cranking", for instance, starting a cold engine. In this condition, the only energy available to turn the engine comes from the starter motor and the battery, and it has been widely assumed that the system acts as a constant power viscometer.