Ventilation duct unit (1, 1') comprising an inlet, an outlet, a flow channel, which extends from the inlet to the outlet, and which is delimited by a wall between the inlet and the outlet, a closing part, which is arranged in the flow channel, and which in an open position enables flow in the flow channel, and in a closed position prevents flow in the flow channel, an actuator, which is configured to move the closing part between the open and the closed position to achieve flow that is defined for the ventilation duct unit in the flow channel, a closing member which as a response to detecting fire, sets the closing part to a predetermined position, a position switch of the closing part, which is in a first state, when the closing part is in said predetermined position, and which is in a second state, when the closing part is not in said predetermined position, and a fire testing unit, which at predetermined times is configured to trigger testing of the fire safety functions, wherein the closing member sets the closing part to said predetermined position, and which after triggering testing of the fire safety functions, is configured to indicate that testing of the fire safety functions was successful, if the fire testing unit detects that the state of the position switch of the closing part has changed in a predetermined way between the first and the second state after the triggering, characterized in that the fire testing unit comprises a clock, and a memory, to which data is saved and which indicates the times when the fire test is to be triggered, and the fire testing unit is arranged to trigger testing of the fire safety functions when the clock indicates a time which corresponds with the triggering time of testing of the fire safety functions saved in the memory, and the fire testing unit and a control unit for the actuator are integrated into one part. an inlet, an outlet, a flow channel, which extends from the inlet to the outlet, and which is delimited by a wall between the inlet and the outlet, a closing part, which is arranged in the flow channel, and which in an open position enables flow in the flow channel, and in a closed position prevents flow in the flow channel, an actuator, which is configured to move the closing part between the open and the closed position to achieve flow that is defined for the ventilation duct unit in the flow channel, a closing member which as a response to detecting fire, sets the closing part to a predetermined position, a position switch of the closing part, which is in a first state, when the closing part is in said predetermined position, and which is in a second state, when the closing part is not in said predetermined position, and a fire testing unit, which at predetermined times is configured to trigger testing of the fire safety functions, wherein the closing member sets the closing part to said predetermined position, and which after triggering testing of the fire safety functions, is configured to indicate that testing of the fire safety functions was successful, if the fire testing unit detects that the state of the position switch of the closing part has changed in a predetermined way between the first and the second state after the triggering, characterized in that the fire testing unit comprises a clock, and a memory, to which data is saved and which indicates the times when the fire test is to be triggered, and the fire testing unit is arranged to trigger testing of the fire safety functions when the clock indicates a time which corresponds with the triggering time of testing of the fire safety functions saved in the memory, and the fire testing unit and a control unit for the actuator are integrated into one part.