feat: added product variants

shop/tests/mixins.py

@@ -2,7 +2,7 @@ from decimal import Decimal
 
 from django.utils.timezone import now
 
-from shop.models import Product, ProductPrice, Tax
+from shop.models import Product, ProductAttribute, ProductAttributeValue, ProductPrice, ProductVariant, Tax
 
 
 class CreateProductsMixin:
@@ -13,3 +13,20 @@ class CreateProductsMixin:
         product = Product.objects.create(sku=sku, name=name, description=description, is_shipping_method=is_shipping)
         ProductPrice.objects.create(price=price, product=product, date=now(), tax=tax, current=True)
         return product
+
+    def create_attribute_value(self, attribute_name='Talla', value='M') -> ProductAttributeValue:
+        attribute, created = ProductAttribute.objects.get_or_create(name=attribute_name)
+        attribute_value, created = ProductAttributeValue.objects.get_or_create(attribute=attribute, value=value)
+        return attribute_value
+
+    def create_product_variant(
+        self, product: Product, sku='000001-V1', price=Decimal('10.00'), stock=Decimal('10'), attribute_values=None
+    ) -> ProductVariant:
+        tax, created = Tax.objects.get_or_create(code='IVA', value=21)
+        variant = ProductVariant.objects.create(product=product, sku=sku, stock=stock)
+
+        if attribute_values:
+            variant.attribute_values.set(attribute_values)
+
+        ProductPrice.objects.create(price=price, variant=variant, date=now(), tax=tax, current=True)
+        return variant

shop/tests/test_variants.py

@@ -0,0 +1,51 @@
+from decimal import Decimal
+
+from django.core.exceptions import ValidationError
+from django.test import TestCase
+
+from shop.models import ProductVariant
+from shop.tests.mixins import CreateProductsMixin
+
+
+class TestProductVariants(TestCase, CreateProductsMixin):
+    def setUp(self):
+        self.product = self.create_product()
+        self.size_m = self.create_attribute_value('Talla', 'M')
+        self.size_l = self.create_attribute_value('Talla', 'L')
+
+    def test_product_without_variants_has_variants_false(self):
+        assert self.product.has_variants is False
+
+    def test_product_with_variants_has_variants_true(self):
+        self.create_product_variant(self.product, sku='V1', attribute_values=[self.size_m])
+
+        assert self.product.has_variants is True
+
+    def test_variant_price_returns_current_price(self):
+        variant = self.create_product_variant(self.product, sku='V1', price=Decimal('15.00'), attribute_values=[self.size_m])
+
+        assert variant.price.price == Decimal('15.00')
+
+    def test_variant_str_includes_attribute_values(self):
+        variant = self.create_product_variant(self.product, sku='V1', attribute_values=[self.size_m])
+
+        assert 'Talla: M' in str(variant)
+
+    def test_min_variant_price_returns_lowest_current_price(self):
+        self.create_product_variant(self.product, sku='V1', price=Decimal('20.00'), attribute_values=[self.size_m])
+        self.create_product_variant(self.product, sku='V2', price=Decimal('12.00'), attribute_values=[self.size_l])
+
+        assert self.product.min_variant_price.price == Decimal('12.00')
+
+    def test_duplicated_attribute_combination_is_invalid(self):
+        self.create_product_variant(self.product, sku='V1', attribute_values=[self.size_m])
+        duplicated = self.create_product_variant(self.product, sku='V2', attribute_values=[self.size_m])
+
+        with self.assertRaises(ValidationError):
+            duplicated.full_clean()
+
+    def test_different_attribute_combination_is_valid(self):
+        self.create_product_variant(self.product, sku='V1', attribute_values=[self.size_m])
+        other = self.create_product_variant(self.product, sku='V2', attribute_values=[self.size_l])
+
+        other.full_clean()