from datetime import timedelta from decimal import Decimal from django.contrib.auth import get_user_model from django.test import TestCase from django.utils import timezone from rest_framework.test import APIClient from shop_management.models.data.account_transaction import AccountTransaction, AccountTransactionType from shop_management.models.data.inventory import InventoryBatch, StockBalance, StockMovement from shop_management.models.data.accounting import JournalEntry from shop_management.models.data.customer import Customer from shop_management.models.data.organization import Warehouse from shop_management.models.data.product import Product from shop_management.models.data.sale import Sale from shop_management.models.data.sale_return import SaleReturn from shop_management.models.data.shop import Shop from shop_management.models.data.shop_account import Account from shop_management.models.data.utils import Currency, Unit from shop_management.services.inventory import receive_stock class SaleReturnLifecycleTests(TestCase): def setUp(self): self.user = get_user_model().objects.create_user(username="returns", password="test", is_staff=True) self.user.allowed_tabs = ["sales", "sale_return"] self.user.save(update_fields=["allowed_tabs"]) self.shop = Shop.objects.create(owner=self.user, name="Kabul") self.warehouse = Warehouse.objects.create(shop=self.shop, code="MAIN", name="Main") self.currency = Currency.objects.create(shop=self.shop, title="AFN") self.account = Account.objects.create(shop=self.shop, name="Cash", currency=self.currency) self.customer = Customer.objects.create(shop=self.shop, name="Registered Customer") self.unit = Unit.objects.create(shop=self.shop, title="Each") self.product = Product.objects.create(shop=self.shop, name="Medicine", default_unit=self.unit, requires_batch=True, requires_expiry=True) self.batch_a = InventoryBatch.objects.create(product=self.product, batch_number="A", expiry_date=timezone.localdate() + timedelta(days=20)) self.batch_b = InventoryBatch.objects.create(product=self.product, batch_number="B", expiry_date=timezone.localdate() + timedelta(days=60)) receive_stock(warehouse=self.warehouse, product=self.product, batch=self.batch_a, quantity=2, unit_cost=10, currency=self.currency) receive_stock(warehouse=self.warehouse, product=self.product, batch=self.batch_b, quantity=4, unit_cost=20, currency=self.currency) self.client = APIClient() self.client.force_authenticate(self.user) response = self.client.post("/api/shop/sales/", { "shop": self.shop.id, "warehouse": self.warehouse.id, "currency": self.currency.id, "customer": self.customer.id, "sales_type": "CASH", "invoice_date": str(timezone.localdate()), "discount_type": "PERCENTAGE", "discount_value": "10", "received_amount": "0", "items": [{"product": self.product.id, "unit": self.unit.id, "quantity": 5, "sale_price": "30"}], }, format="json") self.assertEqual(response.status_code, 201, response.data) self.sale = Sale.objects.get(pk=response.data["id"]) posted = self.client.post(f"/api/shop/sales/{self.sale.id}/post/") self.assertEqual(posted.status_code, 200, posted.data) self.sale.received_amount = Decimal("135") self.sale.save(update_fields=["received_amount"]) StockMovement.objects.filter(movement_type="OPENING").delete() def create_return(self, quantity, cash_refund="0"): response = self.client.post("/api/shop/sale-returns/", { "shop": self.shop.id, "sale": self.sale.id, "reason": "Customer return", "refund_account": self.account.id if Decimal(cash_refund) else None, "cash_refund_amount": cash_refund, "return_items": [{"sale_item": self.sale.sale_items.get().id, "return_quantity": quantity}], }, format="json") self.assertEqual(response.status_code, 201, response.data) return SaleReturn.objects.get(pk=response.data["id"]) def test_partial_return_restores_original_batches_and_discounted_value(self): document = self.create_return(3) self.assertEqual(document.document_status, "DRAFT") self.assertEqual(StockBalance.objects.get(batch=self.batch_a).quantity, 0) response = self.client.post(f"/api/shop/sale-returns/{document.id}/post/") self.assertEqual(response.status_code, 200, response.data) document.refresh_from_db() restorations = list(document.return_items.get().batch_restorations.order_by("batch__batch_number")) self.assertEqual([row.quantity for row in restorations], [Decimal("2"), Decimal("1")]) self.assertEqual(document.total_refound_amount, Decimal("81.00")) self.assertEqual(StockBalance.objects.get(batch=self.batch_a).quantity, 2) self.assertEqual(StockBalance.objects.get(batch=self.batch_b).quantity, 2) def test_multiple_returns_cannot_exceed_sold_quantity_atomically(self): first = self.create_return(4) self.assertEqual(self.client.post(f"/api/shop/sale-returns/{first.id}/post/").status_code, 200) second = self.create_return(2) before = StockBalance.objects.get(batch=self.batch_b).quantity response = self.client.post(f"/api/shop/sale-returns/{second.id}/post/") self.assertEqual(response.status_code, 400) second.refresh_from_db() self.assertEqual(second.document_status, "DRAFT") self.assertEqual(StockBalance.objects.get(batch=self.batch_b).quantity, before) def test_cash_refund_and_void_are_reversed(self): document = self.create_return(2, "40") self.assertEqual(self.client.post(f"/api/shop/sale-returns/{document.id}/post/").status_code, 200) self.assertEqual(AccountTransaction.objects.get().transaction_type, AccountTransactionType.DEBIT) response = self.client.post(f"/api/shop/sale-returns/{document.id}/void/", {"reason": "Return cancelled"}, format="json") self.assertEqual(response.status_code, 200, response.data) document.refresh_from_db() self.assertEqual(document.document_status, "VOID") self.assertEqual(list(AccountTransaction.objects.order_by("id").values_list("transaction_type", flat=True)), ["debit", "credit"]) self.assertEqual(StockBalance.objects.get(batch=self.batch_a).quantity, 0) def test_voiding_sale_cascades_posted_return_without_double_restoring_stock(self): document = self.create_return(2) self.assertEqual( self.client.post(f"/api/shop/sale-returns/{document.id}/post/").status_code, 200, ) response = self.client.post( f"/api/shop/sales/{self.sale.id}/void/", {"reason": "Original invoice cancelled"}, format="json", ) self.assertEqual(response.status_code, 200, response.data) document.refresh_from_db() self.sale.refresh_from_db() self.assertEqual(document.document_status, SaleReturn.DocumentStatus.VOID) self.assertEqual(self.sale.document_status, Sale.DocumentStatus.VOID) self.assertEqual(StockBalance.objects.get(batch=self.batch_a).quantity, Decimal("2")) self.assertEqual(StockBalance.objects.get(batch=self.batch_b).quantity, Decimal("4")) self.assertFalse( JournalEntry.objects.filter( source_type__in=["SALE", "SALE_RETURN"], status=JournalEntry.Status.POSTED, ).exists() )