Implement vi.useFakeTimers, vi.setSystemTime, vi.useRealTimers like vitest

[NateRadebaugh]

What is the problem this feature would solve?

Test file in formatDate.test.ts

import { afterAll, beforeAll, describe, vi } from "vitest";

describe("formatDate", () => {
  beforeAll(() => {
    vi.useFakeTimers();
    vi.setSystemTime(new Date("2021-01-01T18:00:00Z"));
  });

  afterAll(() => {
    vi.useRealTimers();
  });
});

Run:

bun test formatDate

Error:

XXX> bun test formatDate        
bun test v1.1.3 (2615dc74)

XXX\formatDate.test.ts:
2 | import { formatDate } from "XXX/format";
3 | import { afterAll, beforeAll, describe, expect, it, vi } from "vitest";
4 |
5 | describe("formatDate", () => {
6 |   beforeAll(() => {
7 |     vi.useFakeTimers();
        ^
TypeError: vi.useFakeTimers is not a function. (In 'vi.useFakeTimers()', 'vi.useFakeTimers' is undefined)
      at XXX\formatDate.test.ts:7:5
      at XXX\formatDate.test.ts:5:1

 0 pass
 0 fail
Ran 0 tests across 1 files. [107.00ms]

What is the feature you are proposing to solve the problem?

There's already some magic that occurs within bun test when using jest methods via @jest/globals but it'd be great if the same logic could be extended to include vitest helper methods from vi so we don't need to change our test code in order to run with bun test.

What alternatives have you considered?

• Rewrite tests to use @jest/globals. However, jest is much slower than vitest
• Rewrite bun:test. However bun:test does not have first-class vscode extension integration like vitest

[BlakeEddie]

If this is too much work as a quick fix how hard would it be to add to the bunfig.toml the option to use the package.json test script ignoring the bun testing tool?

[NateRadebaugh]

If this is too much work as a quick fix how hard would it be to add to the bunfig.toml the option to use the package.json test script ignoring the bun testing tool?

I don't think that is necessary as a workaround -- we already have the ability to use "bun run test" to run the package.json test script even with bun as the package manager.

My goal here is to be able to use bun in CI for perf before forcing all my devs to worry about installing/using bun explicitly as part of local development, so bun supporting the baked-in vitest functionality is preferred without any other workarounds.