public void GetAllOwners_Sorts_Results_By_Name() { //test one thing and one thing only usually //Arrange var mockOwnerRepository = new Mock <IOwnerRepository>(); var mockLogger = NullLogger <OwnerService> .Instance; //var logger = new Mock<ILogger<OwnerService>>(); // you can have strict or loose mockup var mockMapper = new Mock <IMapper>(); var ownerService = new OwnerService(mockOwnerRepository.Object, mockLogger, mockMapper.Object); //Act var result = ownerService.GetAllOwners(); //Assert Assert.Equal(2, result.Count()); }