Abstract: A pressure sensor assembly (19) for remote testing of a pressure sensor (15) adapted to monitor the air pressure developed in an interior (21) of a container (1), the pressure sensor assembly (19) comprising: an enclosed chamber having (25): a first opening (31) arranged to communicate with the interior of the container (1); and a second opening (33) arranged to communicate with the pressure sensor (15) for monitoring air pressure developed in the interior (21) of the container (1); wherein the chamber (25) defines a channel for transmission of pressure between the first opening (31) and the second opening (33) and wherein a constriction (55) is formed in the channel, the pressure sensor assembly (19) further comprising: an air injection system (45) adapted to inject a test pulse (47) of air into the enclosed chamber (25), between the constriction (55) and the second opening (33), wherein the constriction (55) is configured to create a back pressure in the enclosed chamber (25) in response to the test pulse o