The Hello Test is a very basic data connection test. It detects if the Spartan GoCam is connected to the carrier's data network.
With the camera in Setup mode (GoCam, GoCam 2) or ON (all GoLive models and Ghost) and connected to the cellular network (the carrier name and signal strength bars appear at the top of the screen), press Menu, Wireless (last tab) > scroll down to Diagnostic > Hello Test.
If the camera screen shows Successful!, your camera is connected to the cellular network. If it says Failed, it is not. You'll need to be sure that you have an active data plan and are using a "to spec" SD card.