This post is about how to go take a driving test alone, that is, without being accompanied by anyone. I’m in Pennsylvania, so the information here may not apply to other states.
If you have an international drivers license and your name is on the insurance policy of your friend’s car, then you can drive his/her car to a test center and take a driving test alone.
Most big car rental companies (e.g., Hertz, Avis, Enterprise) do NOT allow their cars to be used for a driving test even if the driver is eligible to rent and drive their cars (using an international drivers license). Drivers license centers are highly unlikely to let you take a driving test in this case.