public async Task GivenItemNotInCart_AddOrUpdate_SetsCountToOne() { //arrange var actual = new Repositories.Entities.Cart { Count = 0 }; Mapper.Setup(mapper => mapper.Map <Repositories.Entities.Cart>(It.IsAny <Cart>())).Returns(actual); var sut = new CartService(CartCalculatorService.Object, CartRepository.Object, Mapper.Object); //act await sut.AddOrUpdate(new Cart()); //assert Assert.True(actual.Count == 1); }