feat(F-138): completed feature

project/src/modules/cart/tests/cart-service.test.ts

@@ -37,6 +37,7 @@ const pricing: PricingServicePort = {
   setVariantPrice: async () => {
     throw new Error('not needed');
   },
+  seedVariantPrice: async () => undefined,
   calculate: async ({ variantId, quantity }) => ({
     variantId,
     quantity,

project/src/modules/catalog/api/catalog.routes.ts

@@ -41,6 +41,7 @@ import type { Product } from '../domain/product.js';
 import { PRODUCT_ATTRIBUTES, PRODUCT_STATES } from '../domain/product.js';
 import type { ProductRichData, ProductVariant } from '../domain/variant.js';
 import { NUTRITION_SOURCES } from '../domain/variant.js';
+import type { PricingServicePort } from '../../pricing/index.js';
 import { LocalProductImageStorage } from '../infrastructure/local-product-image-storage.js';
 import { PgProductImageRepository } from '../infrastructure/pg-product-image-repository.js';
 import { PgProductRepository } from '../infrastructure/pg-product-repository.js';
@@ -56,6 +57,7 @@ export interface CatalogRoutesDeps {
   pool: pg.Pool;
   authenticate: Authenticate;
   logger?: CatalogSearchLogger;
+  pricing: PricingServicePort;
 }
 
 const slugSchema = z
@@ -178,7 +180,7 @@ export async function registerCatalogRoutes(
   const createProduct = new CreateProduct(repository);
   const updateProduct = new UpdateProduct(repository);
   const listVariants = new ListProductVariants(variants);
-  const createVariant = new CreateProductVariant(repository, variants);
+  const createVariant = new CreateProductVariant(repository, variants, deps.pricing);
   const updateVariant = new UpdateProductVariant(variants);
   const upsertRichData = new UpsertProductRichData(repository, richData);
   const listImages = new ListProductImages(images);

project/src/modules/catalog/application/variant-use-cases.ts

@@ -3,6 +3,7 @@ import type {
   ProductRichDataRepository,
   ProductVariantRepository,
 } from '../domain/ports.js';
+import type { PricingServicePort } from '../../pricing/index.js';
 import type {
   NewProductVariant,
   ProductRichData,
@@ -23,13 +24,23 @@ export class CreateProductVariant {
   constructor(
     private readonly products: ProductRepository,
     private readonly variants: ProductVariantRepository,
+    private readonly pricing: PricingServicePort,
   ) {}
 
   async execute(productId: string, input: NewProductVariant): Promise<ProductVariant | undefined> {
     if (!(await this.products.findById(productId))) {
       return undefined;
     }
-    return this.variants.create(productId, input);
+    const variant = await this.variants.create(productId, input);
+    // Best-effort: seed a default price row immediately so GET /pricing/variants/:id
+    // never 404s after variant creation (F-138). The variant already persisted, so a
+    // seed failure must not fail or roll back variant creation itself.
+    try {
+      await this.pricing.seedVariantPrice(variant.id);
+    } catch (error) {
+      void error;
+    }
+    return variant;
   }
 }
 

project/src/modules/catalog/tests/variant-use-cases.test.ts

@@ -0,0 +1,126 @@
+import { describe, expect, it } from 'vitest';
+import { CreateProductVariant } from '../application/variant-use-cases.js';
+import type { PricingServicePort, PriceCalculation, VariantPrice } from '../../pricing/index.js';
+import type { NewProductVariant, ProductVariant } from '../domain/variant.js';
+import type { Product } from '../domain/product.js';
+import type {
+  ProductRepository,
+  ProductVariantRepository,
+} from '../domain/ports.js';
+
+function makeVariant(productId: string, sku: string): ProductVariant {
+  return {
+    id: 'variant-1',
+    productId,
+    sku,
+    ean: null,
+    attributes: {},
+    createdAt: new Date('2026-01-01T00:00:00Z'),
+    updatedAt: new Date('2026-01-01T00:00:00Z'),
+  };
+}
+
+class FakeProductRepository implements ProductRepository {
+  public readonly existing = new Set<string>();
+  async findById(id: string): Promise<Product | undefined> {
+    return this.existing.has(id) ? ({ id } as unknown as Product) : undefined;
+  }
+  async create(): Promise<Product> {
+    throw new Error('not implemented');
+  }
+  async findActiveBySlug(): Promise<Product | undefined> {
+    throw new Error('not implemented');
+  }
+  async update(): Promise<Product | undefined> {
+    throw new Error('not implemented');
+  }
+  async delete(): Promise<void> {
+    throw new Error('not implemented');
+  }
+  async listAll(): Promise<{ items: Product[]; total: number }> {
+    throw new Error('not implemented');
+  }
+  async categoriesExist(): Promise<boolean> {
+    throw new Error('not implemented');
+  }
+  async brandExists(): Promise<boolean> {
+    throw new Error('not implemented');
+  }
+}
+
+class FakeProductVariantRepository implements ProductVariantRepository {
+  public lastInput: NewProductVariant | undefined;
+  constructor(public readonly variant: ProductVariant = makeVariant('p', 'SKU-X')) {}
+  async create(_productId: string, input: NewProductVariant): Promise<ProductVariant> {
+    this.lastInput = input;
+    return this.variant;
+  }
+  async listByProductId(): Promise<ProductVariant[]> {
+    throw new Error('not implemented');
+  }
+  async update(): Promise<ProductVariant | undefined> {
+    throw new Error('not implemented');
+  }
+}
+
+class FakePricingService implements PricingServicePort {
+  public seedCalls: string[] = [];
+  public seedShouldThrow = false;
+  async seedVariantPrice(variantId: string): Promise<void> {
+    this.seedCalls.push(variantId);
+    if (this.seedShouldThrow) throw new Error('seed boom');
+  }
+  async calculate(): Promise<PriceCalculation> {
+    throw new Error('not implemented');
+  }
+  async getVariantPrice(): Promise<VariantPrice | undefined> {
+    throw new Error('not implemented');
+  }
+  async setVariantPrice(): Promise<VariantPrice> {
+    throw new Error('not implemented');
+  }
+}
+
+describe('CreateProductVariant', () => {
+  it('seeds a default price row immediately after creating the variant (F-138 AC1, AC4)', async () => {
+    const products = new FakeProductRepository();
+    products.existing.add('product-1');
+    const variant = makeVariant('product-1', 'SKU-X');
+    const variants = new FakeProductVariantRepository(variant);
+    const pricing = new FakePricingService();
+    const usecase = new CreateProductVariant(products, variants, pricing);
+
+    const result = await usecase.execute('product-1', { sku: 'SKU-X' });
+
+    expect(result).toBe(variant);
+    expect(variants.lastInput?.sku).toBe('SKU-X');
+    expect(pricing.seedCalls).toEqual(['variant-1']);
+  });
+
+  it('does not seed a price row when the product does not exist (F-138 AC1)', async () => {
+    const products = new FakeProductRepository();
+    const variants = new FakeProductVariantRepository();
+    const pricing = new FakePricingService();
+    const usecase = new CreateProductVariant(products, variants, pricing);
+
+    const result = await usecase.execute('product-2', { sku: 'SKU-X' });
+
+    expect(result).toBeUndefined();
+    expect(pricing.seedCalls).toEqual([]);
+  });
+
+  it('returns the created variant even if seeding the price row fails (F-138 AC3, best-effort)', async () => {
+    const products = new FakeProductRepository();
+    products.existing.add('product-1');
+    const variant = makeVariant('product-1', 'SKU-X');
+    const variants = new FakeProductVariantRepository(variant);
+    const pricing = new FakePricingService();
+    pricing.seedShouldThrow = true;
+    const usecase = new CreateProductVariant(products, variants, pricing);
+
+    const result = await usecase.execute('product-1', { sku: 'SKU-X' });
+
+    expect(result).toBe(variant);
+    expect(pricing.seedCalls).toEqual(['variant-1']);
+  });
+});

project/src/modules/checkout/tests/checkout-service.test.ts

@@ -53,6 +53,7 @@ function buildDeps(
   const pricing: PricingServicePort = {
     getVariantPrice: async () => undefined,
     setVariantPrice: async () => ({}) as never,
+    seedVariantPrice: async () => undefined,
     calculate: async () => PRICE,
   };
   const reserved = { calls: [] as Array<{ variantId: string; quantity: number }> };
@@ -234,6 +235,7 @@ describe('CheckoutService', () => {
       pricing: {
         getVariantPrice: async () => undefined,
         setVariantPrice: async () => ({}) as never,
+        seedVariantPrice: async () => undefined,
         calculate: async () => PRICE,
       },
       inventory: {

project/src/modules/pricing/application/pricing-service.ts

@@ -42,6 +42,10 @@ export class PricingService implements PricingServicePort {
     ensureNonNegativeInteger(input.netUnitAmountCents, 'Price must be a non-negative integer');
     return this.repository.setVariantPrice(input);
   }
+
+  async seedVariantPrice(variantId: string): Promise<void> {
+    await this.repository.seedVariantPrice(variantId);
+  }
 }
 
 function ensurePositiveInteger(value: number, message: string): void {

project/src/modules/pricing/domain/ports.ts

@@ -9,9 +9,16 @@ export interface PricingService {
   calculate(input: PriceCalculationCommand): Promise<PriceCalculation>;
   getVariantPrice(variantId: string): Promise<VariantPrice | undefined>;
   setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice>;
+  /**
+   * Seeds a neutral default price row for a freshly created variant so that
+   * GET /pricing/variants/:id never 404s right after creation (F-138). Idempotent:
+   * no-op when a row already exists for the given variant_id.
+   */
+  seedVariantPrice(variantId: string): Promise<void>;
 }
 
 export interface PricingRepository {
   findByVariantId(variantId: string): Promise<VariantPrice | undefined>;
   setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice>;
+  seedVariantPrice(variantId: string): Promise<void>;
 }

project/src/modules/pricing/infrastructure/pg-pricing-repository.ts

@@ -25,6 +25,15 @@ export class PgPricingRepository implements PricingRepository {
     return row ? toVariantPrice(row) : undefined;
   }
 
+  async seedVariantPrice(variantId: string): Promise<void> {
+    await this.pool.query(
+      `INSERT INTO pricing_variant_prices (variant_id, net_unit_amount_cents, offer_cents, cost_cents, vat_rate)
+       VALUES ($1, 0, NULL, NULL, 'general')
+       ON CONFLICT (variant_id) DO NOTHING`,
+      [variantId],
+    );
+  }
+
   async setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice> {
     const client = await this.pool.connect();
     try {

project/src/modules/pricing/tests/pricing-service.test.ts

@@ -19,6 +19,7 @@ function repository(overrides: Partial<PricingRepository> = {}): PricingReposito
   return {
     findByVariantId: async () => PRICE,
     setVariantPrice: async (_input: SetVariantPriceCommand) => PRICE,
+    seedVariantPrice: async () => undefined,
     ...overrides,
   };
 }