public void CallProceedOnce() { // Arrange var loggerMock = new Mock <ILogger>(); var writerMock = new Mock <IWriter>(); var invocationMock = new Mock <IInvocation>(); invocationMock.Setup(i => i.Proceed()); LogErrorInterceptor logErrorInterceptor = new LogErrorInterceptor(loggerMock.Object, writerMock.Object); // Act logErrorInterceptor.Intercept(invocationMock.Object); // Assert invocationMock.Verify(i => i.Proceed(), Times.Once()); }