A test fixture used to calibrate an electronic device is disclosed. The test fixture includes several modules positioned on a rack. The modules may include either a stimulus member or light-absorbing material. An actuator connected to an end unit is configured to engage any one of the several modules and transport the module from the rack to a location over the electronic device. At least one module can calibrate a touch sensor of the electronic device, while at least another module can calibrate a proximity sensor of the electronic device. In some cases, an additional module is configured to calibrate a touch sensor of a second electronic device, such as a previous generation of an electronic device or an electronic device having a different dimension. The electronic device can lie on a cradle that may be identified by a feature on the cradle, such as a magnet.