If you've booked yourself a practical driving test, the DSA will have sent you an appointment letter giving full details of date, time and location of your car or motocycle driving test. It is important that you throughly read this letter even if you are attending the assessment in a driving school car, as they will provide you with important information that you need to know, some of which if you don't adhere to will stop the test from going ahead.
I've mentioned before that you should not arrive late for a driving test, so you will obviously need to know where the test centre is located and how to get there if you are using a private car for the test. The letter also gives details of the conditions that your driving test car needs to be in (roadworthy, displaying "L" plates, interior mirror for examiner, all lights fully functioning), and the identification documents that you need to bring with you.
Note that you will not be able to take the driving test without your licence counterpart, or if your private car has a safety recall issue that has not been rectified. All of this information is on your DSA appoinment letter, so familiarise yourself with the test requirements. You should however be able to take the test if you forgot or didn't get your apointment letter in the post after apply online via the direct.gov website and thus don't have a letter with you, as long as you've got your full identification documents, the same applies to the theory test certificate.
