أفضل ذكاء اصطناعي لـ Write unit tests for existing code

import { formatPrice } from './formatPrice'; describe('formatPrice', () => { describe('happy path', () => { it('formats a whole-number USD amount with two decimals', () => { expect(formatPrice(10, '$')).toBe('$10.00'); }); it('formats a decimal amount, rounding to two places', () => { expect(formatPrice(10.567, '$')).toBe('$10.57'); }); }); describe('boundary inputs', () => { it('formats zero as $0.00, not "$" alone', () => { expect(formatPrice(0, '$')).toBe('$0.00'); }); it('formats negative amounts with the minus before the currency', () => { // Documents current behavior. If this should output "-$5.00" instead // of "$-5.00", that's a real bug — but the test pins the existing contract. expect(formatPrice(-5, '$')).toBe('$-5.00'); }); it('handles very small fractional amounts without losing precision', () => { expect(formatPrice(0.005, '$')).toBe('$0.01'); expect(formatPrice(0.004, '$')).toBe('$0.00'); }); }); describe('error handling', () => { it('returns "$NaN" when amount is NaN — flag as unwanted upstream', () => { // Not validating here is intentional; callers should not pass NaN. // This test pins the current behavior so a sudden change shows up in CI. expect(formatPrice(NaN, '$')).toBe('$NaN'); }); }); describe('intentionally NOT covered', () => { // - Multi-currency formatting (€, £, ¥ before vs after) — this code doesn't claim to handle locale. // - Locale-specific decimal separators (1.000,00 vs 1,000.00) — out of scope; if needed, swap to Intl.NumberFormat. // - Currency strings longer than one character ("USD") — passes through unmodified, that's fine. }); });