Files
sendou.ink/app/features/lfg/core/timezone.test.ts
2026-08-05 16:40:44 +03:00

23 lines
861 B
TypeScript

import { describe, expect, test } from "vitest";
import { hourDifferenceBetweenTimezones } from "./timezone";
describe("hourDifferenceBetweenTimezones", () => {
// Pacific/Kiritimati is UTC+14 and Pacific/Honolulu is UTC-10, neither
// observes DST -> their local clocks show the exact same time year round
test("timezones with identical local clock time across the date line have zero difference", () => {
expect(
hourDifferenceBetweenTimezones("Pacific/Kiritimati", "Pacific/Honolulu"),
).toBe(0);
});
// Asia/Tokyo (UTC+9) and Pacific/Honolulu (UTC-10) are 19 hours apart on
// paper but their local clocks only differ by 5 hours
test("difference is never more than 12 hours in either direction", () => {
expect(
Math.abs(
hourDifferenceBetweenTimezones("Asia/Tokyo", "Pacific/Honolulu"),
),
).toBeLessThanOrEqual(12);
});
});