public void ShouldCallTripsServiceMethodGetUserById() { //Arrange var tripsServiceMock = new Mock <ITripsService>(); tripsServiceMock.Setup(s => s.GetTripById(It.IsAny <int>())) .Returns(new Trip()); var controller = new TripController( this.usersServiceMock.Object, tripsServiceMock.Object, this.cacheServiceMock.Object, this.mapperMock.Object); //Act controller.ById(ValidIdString); //Assert tripsServiceMock.Verify(s => s.GetTripById(It.IsAny <string>()), Times.Once); }