What is the ride request pickup.eta value once driver has arrived to pickup location? Is it set to 0? Is it not provided? Else?
Also, is there a way to set driver's current location on sandbox testing?
From what we see, pickup ETA usually will only count down to 1. We don't see the behavior of it being '0'. Once the driver arrives and the trip starts, the pickup ETA will disappear. Essentially you should show whatever the "pickup ETA" is if the value is there.
"Also, is there a way to set driver's current location on sandbox testing?" - There is not, but you can simulate the change in behavior from arriving to in progress in the Sandbox.
Hope that helps!