What is the proper procedure for conducting a 'tug test' on a newly coupled semi-trailer?

1. Set the trailer brakes, release the tractor parking brakes, gently apply engine power in forward low gear to feel positive resistance against the kingpin, then inspect the coupling visually
2. Drive 10 kilometres at highway speed to see if the trailer stays attached
3. Back the tractor with full throttle into the trailer until the chassis shakes
4. Disconnect the red air line and pull the handbrake