MCP Time Server Node

import { resolveTimezone } from '../../src/utils/timezoneUtils'; describe('resolveTimezone', () => { const systemTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone; describe('core behavior', () => { it('should return system timezone when undefined', () => { const result = resolveTimezone(undefined, systemTimezone); expect(result).toBe(systemTimezone); }); it('should return UTC when empty string', () => { const result = resolveTimezone('', systemTimezone); expect(result).toBe('UTC'); }); it('should return specified timezone when provided', () => { const result = resolveTimezone('America/New_York', systemTimezone); expect(result).toBe('America/New_York'); }); it('should handle various IANA timezones', () => { const timezones = ['Europe/London', 'Asia/Tokyo', 'Australia/Sydney', 'America/Los_Angeles']; timezones.forEach((tz) => { const result = resolveTimezone(tz, systemTimezone); expect(result).toBe(tz); }); }); }); describe('edge cases', () => { it('should use custom default timezone', () => { const customDefault = 'Europe/Paris'; const result = resolveTimezone(undefined, customDefault); expect(result).toBe(customDefault); }); it('should handle empty string consistently regardless of default', () => { const result1 = resolveTimezone('', 'America/New_York'); const result2 = resolveTimezone('', 'Europe/London'); const result3 = resolveTimezone('', systemTimezone); expect(result1).toBe('UTC'); expect(result2).toBe('UTC'); expect(result3).toBe('UTC'); }); it('should preserve non-empty whitespace strings', () => { // These would fail validation elsewhere, but resolveTimezone doesn't validate const result = resolveTimezone(' ', systemTimezone); expect(result).toBe(' '); }); }); describe('type safety', () => { it('should handle null as undefined (edge case)', () => { // This shouldn't happen in TypeScript, but verify behavior const result = resolveTimezone(null as any, systemTimezone); expect(result).toBe(systemTimezone); }); }); describe('consistency with project convention', () => { it('should follow documented timezone handling rules', () => { // From CLAUDE.md: // - undefined or missing timezone: Interpreted as the system's local timezone // - "" (empty string): Interpreted as UTC // - Any other string: Interpreted as that specific IANA timezone const testCases = [ { input: undefined, expected: systemTimezone }, { input: '', expected: 'UTC' }, { input: 'America/Chicago', expected: 'America/Chicago' }, ]; testCases.forEach(({ input, expected }) => { const result = resolveTimezone(input, systemTimezone); expect(result).toBe(expected); }); }); }); });