Thanks for providing the model. I see that you are using the Measurement Output block.
In Test mode, the output of the model is only stored (and recorded as an Operation or Measurement object of a virtual device) and not sent back to the device. Virtual devices are not shown in the Device Management application. Virtual devices are objects in the Cumulocity IoT inventory with a c8y_VirtualDevice property. This property refers to the identifier of the real device of which the virtual device is a copy.
Also please note, even though device management UI does not show virtual devices, you can open the device specific page using the ID of the virtual device.