not a written test, an 8710. If the check airman were authorized to give ATP practical exams in that aircraft then you get get an ATP out of it. Some companies do that but it is rare. When taking a 135 test you can legally take it with the FAA instead of the company check airman and they can issue the ATP. That is only if the company allows that option. If you take the ride with the FAA then you have to be dead on where as if you go up with the company man and botch something, the check airman has the option to pause the checkride and do some retraining and then resume the checkride.