public void Return_Customer_List_When_Records_Exist()
        {
            MockCustomerRepo.Setup(c => c.FetchAllCustomers()).ReturnsAsync(ListOfCustomers());

            var result = CustomerServiceSut.FetchAllCustomers();

            Assert.NotNull(result);
            Assert.IsAssignableFrom <Task <IEnumerable <CustomerDto> > >(result);
        }
        public async Task Return_Empty_When_No_Records_Exist()
        {
            MockCustomerRepo.Setup(c => c.FetchAllCustomers()).ReturnsAsync(new List <Customer>());

            var result = await CustomerServiceSut.FetchAllCustomers();

            Assert.NotNull(result);
            Assert.IsAssignableFrom <IEnumerable <CustomerDto> >(result);
            Assert.Empty(result);
        }