public async void GetMakeAsync_Returns_IVehicleMake() { repoMock.Setup(s => s.GetAsync(It.IsAny <Guid>())).Returns(Task.FromResult(new Mock <IVehicleMake>().Object)); uowMock.SetupGet(s => s.Makers).Returns(repoMock.Object); var makeService = new VehicleMakeService(uowMock.Object); var make = await makeService.GetMakeAsync(Guid.NewGuid()); //Assert Assert.NotNull(make); Assert.IsAssignableFrom <IVehicleMake>(make); }