groceries: nightly AH/Jumbo catalogue import, unit-price normalisation, product groups and compare UI

src/lib/groceries.test.ts

@@ -0,0 +1,44 @@
+import { describe, expect, it } from 'vitest';
+import { cheapest, formatAmount, formatUnitPrice, sortByPrice, type PricedItem } from './groceries';
+
+const it_ = (
+	id: number,
+	storeId: number,
+	price: number,
+	unit: number,
+	promo: number | null = null
+): PricedItem => ({
+	id,
+	storeId,
+	priceCents: price,
+	promoPriceCents: promo,
+	unitPriceCents: unit,
+	promoUnitPriceCents: promo == null ? null : Math.round((unit * promo) / price),
+	available: true
+});
+
+describe('grocery price helpers', () => {
+	const items = [
+		it_(1, 1, 119, 119),
+		it_(2, 1, 165, 110),
+		it_(3, 2, 115, 115),
+		it_(4, 2, 200, 200, 100)
+	];
+	it('finds the cheapest by unit price, promos included', () => {
+		const c = cheapest(items, 'unit');
+		expect(c.overall).toBe(4);
+		expect([...c.perStore].sort()).toEqual([2, 4]);
+	});
+	it('finds the cheapest by pack price', () => {
+		expect(cheapest(items, 'pack').overall).toBe(4);
+		expect(cheapest(items.slice(0, 3), 'pack').overall).toBe(3);
+	});
+	it('sorts by unit price', () => {
+		expect(sortByPrice(items, 'unit').map((i) => i.id)).toEqual([4, 2, 3, 1]);
+	});
+	it('formats', () => {
+		expect(formatUnitPrice(250, 'kg')).toMatch(/2,50\/kg$/);
+		expect(formatAmount(1.98, 'l')).toBe('1,98 L');
+		expect(formatUnitPrice(null, 'kg')).toBeNull();
+	});
+});