public async Task AddingAnInvoice_ShouldBeSaved()
        {
            var invoiceItem = ApiDtoGenerator.InvoiceItemGenerator().Generate();
            var apiResult   = await _sut.Post(invoiceItem);

            using (new AssertionScope())
            {
                apiResult.Result.Should().BeOfType <OkObjectResult>();

                await _invoiceRepository.Received(1).AddAsync(Arg.Any <Invoice>());
            }
        }
        public void WhenMapFromInvoice_To_InvoiceDto_AllPropertiesShouldBeMapped()
        {
            var item   = ApiDtoGenerator.InvoiceItemGenerator().Generate();
            var entity = _sut.Map(item);

            using (new AssertionScope())
            {
                item.Date.Should().Be(entity.Date);
                item.CustomerId.Should().Be(entity.Customer.Id);
                item.Summary.Should().Be(entity.Summary);
                item.TotalAmount.Should().Be(entity.TotalAmount);
                item.Id.Should().Be(entity.Id);
            }
        }