public void _inPipe_ContentStatusChangedEventHandler_Fires_Input_AvailabilityChangedEvent() { //Arrange var port = new InputDataPort(); var helper= new HelperForInputPorts(); var mockPipe = new Mock<IDataPipe>(); port.InputAvailabilityChanged += new InputAvailabilityChangedEventHandler<IInputDataPort, InputAvailabilityChangedEventArgs> (helper.InputAvailabilityChanged_DummyHandler); var ea = new PipeStatusChangeEventArgs(PayLoadStatus.Unavailable, PayLoadStatus.Available); //Act port._inPipe_ContentStatusChanged(mockPipe.Object, ea); //Assert Assert.Equal(1, helper.InputAvailabilityChanged_TimesCalled); Assert.NotNull(helper.RecievedEventArgs); }