Testing with Doran

Anything that reads "now" — DoranDate.now(), today, isToday, fromNow, isBetween(now) — is hard to test when the clock keeps moving. Doran ships a freezable clock so you can pin "now" without monkey-patching the global Date (no MockDate, no jest.useFakeTimers() required).

freeze — pin the clock for one block

import { DoranDate, freeze } from '@doranjs/core';

freeze(DoranDate.fromJalali(1405, 1, 1), () => {
  DoranDate.now().format('YYYY/MM/DD'); // always "۱۴۰۵/۰۱/۰۱"
  DoranDate.fromJalali(1405, 1, 1).isToday(); // true
});
// outside the block, now() is the real time again

freeze restores the previous clock automatically — even if the callback throws, and even if it's async (the clock is restored when the returned promise settles):

await freeze(fixed, async () => {
  await doSomethingThatReadsNow();
});

setNow / resetNow — pin the clock for a whole suite

setNow accepts a fixed instant (number epoch ms, Date, or DoranDate) or a function re-evaluated on every read (for a controllable, advancing clock).

Vitest

import { afterEach, expect, it } from 'vitest';
import { DoranDate } from '@doranjs/core';

afterEach(() => DoranDate.resetNow());

it('greets based on the frozen day', () => {
  DoranDate.setNow(DoranDate.fromJalali(1405, 1, 1));
  expect(DoranDate.now().format('dddd')).toBe('شنبه');
});

it('advances time under control', () => {
  let clock = Date.UTC(2026, 0, 1);
  DoranDate.setNow(() => clock); // function source — re-read each call
  const a = DoranDate.now();
  clock += 86_400_000; // +1 day
  expect(DoranDate.now().diff(a, 'day')).toBe(1);
});

Jest

import { DoranDate } from '@doranjs/core';

afterEach(() => DoranDate.resetNow());

test('fromNow is deterministic', () => {
  DoranDate.setNow(DoranDate.fromJalali(1405, 1, 1));
  expect(DoranDate.fromJalali(1405, 1, 1).addDays(-1).fromNow()).toBe('یک روز پیش');
});

Always reset

Call DoranDate.resetNow() in afterEach (or use freeze, which auto-restores) so a frozen clock never leaks into the next test.