A test device configured to test a milking machine, said test device comprising: a fluid flow conduit (2), an air flow regulator (5) arranged to regulate the air flow in the fluid flow conduit (2), a pressure sensor (3) arranged to measure the pressure in the fluid flow conduit (2), and an air flow meter (4) arranged to measure the air flow rate in the fluid flow conduit (2), wherein the fluid flow conduit (2) is arranged to be connected to a vacuum pump (6) of a milking machine during testing of said milking machine by means of the test device, such that a pressure is generated in the fluid flow conduit (2) by the action of the vacuum pump (6).The test device comprises a control unit (16) configured to control the operation of the air flow regulator (5) and thereby regulate the air flow rate in the fluid flow conduit (2) on basis of the measurement performed by said one of the pressure sensor (3) and the air flow meter (4), and the control unit (16) is configured to control the operation of the air flow regulator (5) and said one of the pressure sensor (3) and the air flow meter (4) such that a closed loop is conducted in which either the measured pressure or the measured air flow rate is used as the basis for changing the air flow rate by control of the air flow regulator (5) until the moment in which the measured pressure or measured air flow rate reaches a predetermined value, and the control unit (16) is arranged to initiate measurement operation of the other one of said pressure sensor (3) and air flow meter (4) when said measured pressure or measured air flow rate measured in said closed loop reaches the predetermined value.La présente invention décrit un dispositif de test conçu pour tester une machine à traire, ledit dispositif de test comprenant : un conduit d'écoulement de liquide (2), un régulateur d'écoulement d'air (5) conçu pour réguler l'écoulement d'air dans le conduit d'écoulement de liquide (2), un détecteur de pression (3) conçu pour mesurer la p
