A method for verifying compliance of a communication device with one or more requirement specifications is disclosed. The method comprises establishing a link between a test system and the communication device, wherein the establishing comprises configuring one or more bearers and one or more control channels; closing a test loop comprising the test system and the communication device, wherein the closing comprises activating a test loop function of the communication device; sending data in a downlink of the test loop from the test system to the communication device; receiving the data at the communication device; transferring at least some of the data to an uplink transmission arrangement of the communication device after a specific event has occurred; and verifying, at the test system, transmission in an uplink of the test loop from the communication device to the test system. Corresponding test system and test loop function arrangement are also disclosed.