A test system disposed in a vehicle to repetitively reproduce a driving situation based on a predetermined vehicle speed and a method for controlling, may include determining, by a test controller, at least one of a first value representing an accelerator pedal sensor (APS) command value corresponding to a vehicle speed profile in a specific mode or a second value representing a brake pedal sensor (BPS) command value corresponding to the vehicle speed profile when the vehicle speed profile is determined, converting, by the test controller, at least one of the determined first value or the determined second value, and sending the converted voltage signal from the test controller to a power train controller.