One simple test that could be done would be to test it's comprehension, logic, and reasoning. A robotic computer brain would be capable of following far more complex questions than a human would be. With a lengthy question, a human is going to become lost be unable to follow what is being asked. With a robot, it's not going to have those problems with recollection or data retrieval.
As a result, the robot could follow a (for example) three-page long spoken question, reason out the logical answer based upon all the information of that question, and then make it's reply.