The examiner will NOT tell you to move to the right lane after turning left. You must do that automatically. Only if the examiner tells you to turn left in the next couple of blocks do you stay in the left lane. OR the road that you're on narrows to one lane and you have to merge left. Slower traffic must stay right - this applies to all traffic, both in the city and on the highway. And because you are going to be travelling the speed limit for your test, you are going to be travelling slower than the traffic flow.