public async void GetModelAsync_Returns_IVehicleModel() { repoMock.Setup(s => s.GetAsync(It.IsAny <Guid>())).Returns(Task.FromResult(new Mock <IVehicleModel>().Object)); uowMock.SetupGet(s => s.Models).Returns(repoMock.Object); var modelService = new VehicleModelService(uowMock.Object); var model = await modelService.GetModelAsync(Guid.NewGuid()); //Assert Assert.NotNull(model); Assert.IsAssignableFrom <IVehicleModel>(model); }