feat(shopping): addRecipeToCart (idempotent via ON CONFLICT)

tests/integration/shopping-repository.test.ts

@@ -0,0 +1,65 @@
+import { describe, it, expect } from 'vitest';
+import { openInMemoryForTest } from '../../src/lib/server/db';
+import { insertRecipe } from '../../src/lib/server/recipes/repository';
+import {
+  addRecipeToCart,
+  listShoppingList
+} from '../../src/lib/server/shopping/repository';
+import type { Recipe } from '../../src/lib/types';
+
+function recipe(overrides: Partial<Recipe> = {}): Recipe {
+  return {
+    id: null,
+    title: 'Test',
+    description: null,
+    source_url: null,
+    source_domain: null,
+    image_path: null,
+    servings_default: 4,
+    servings_unit: null,
+    prep_time_min: null,
+    cook_time_min: null,
+    total_time_min: null,
+    cuisine: null,
+    category: null,
+    ingredients: [],
+    steps: [],
+    tags: [],
+    ...overrides
+  };
+}
+
+describe('addRecipeToCart', () => {
+  it('inserts recipe with default servings from recipe.servings_default', () => {
+    const db = openInMemoryForTest();
+    const id = insertRecipe(db, recipe({ title: 'Pasta', servings_default: 4 }));
+    addRecipeToCart(db, id, null);
+    const snap = listShoppingList(db);
+    expect(snap.recipes).toHaveLength(1);
+    expect(snap.recipes[0].servings).toBe(4);
+  });
+
+  it('respects explicit servings override', () => {
+    const db = openInMemoryForTest();
+    const id = insertRecipe(db, recipe({ servings_default: 4 }));
+    addRecipeToCart(db, id, null, 2);
+    expect(listShoppingList(db).recipes[0].servings).toBe(2);
+  });
+
+  it('is idempotent: second insert updates servings, not fails', () => {
+    const db = openInMemoryForTest();
+    const id = insertRecipe(db, recipe({ servings_default: 4 }));
+    addRecipeToCart(db, id, null, 2);
+    addRecipeToCart(db, id, null, 6);
+    const snap = listShoppingList(db);
+    expect(snap.recipes).toHaveLength(1);
+    expect(snap.recipes[0].servings).toBe(6);
+  });
+
+  it('falls back to servings=4 when recipe has no default', () => {
+    const db = openInMemoryForTest();
+    const id = insertRecipe(db, recipe({ servings_default: null }));
+    addRecipeToCart(db, id, null);
+    expect(listShoppingList(db).recipes[0].servings).toBe(4);
+  });
+});