Support jest plugins that use jest globals (jest is not defined)

[fregante]

Clear and concise description of the problem

I'm trying to use https://github.com/clarkbw/jest-webextension-mock in Vitest but it fails on load even if I use globals: true because the package expects the jest global

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    globals: true,
    setupFiles: [
      "jest-webextension-mock"
    ]
  },
})

Suggested solution

Add jest global in dependencies as a tentative compatibility layer, optionally.

Alternative

Add explicit vitest support to every single package I try using 😰 with productivity going 📉

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[fregante]

I also tried setting the jest global via setupFiles but that didn't reach the dependency:

import {defineConfig} from 'vitest/config';

export default defineConfig({
	test: {
		globals: true,
		setupFiles: [
			'./vitest.setup.js',
			'jest-webextension-mock',
		],
	},
});

// vitest.setup.js
import {vi} from 'vitest';

global.jest = vi;

This was also suggested by a member elsewhere: #1193 (comment)

[sheremet-va]

You can add jest global before importing setup file:

globalThis.jest = vi
import "jest-webextension-mock"

[fregante]

That won't shouldn't work because import statements are hoisted, can that be documented or made it easier as I suggested?

[sheremet-va]

That won't work because import statements are hoisted

Try before commenting, please. Import statements are not hoisted in Vitest to support module mocking.

If you are too afraid to break something, you can use await import

[sheremet-va]

can that be documented or made it easier as I suggested?

Can be documented, yes.

We will never add jest global to Vitest. Other solutions are welcome. For example, we can add "prepareSetupFiles", since they are called in parallel and can't reliably affect each other.

[fregante]

How come my previous example didn't work? #2667 (comment)

I assume setupFiles are meant to create globals among other things

[sheremet-va]

How come my previous example didn't work? #2667 (comment)

I assume setupFiles are meant to create globals among other things

Yes. They are running in parallel, not sequential, so it's possible mock resolved before globals were setup.

[o-alexandrov]

Since there's vi.importActual, could you please clarify plans to support jest plugins that use:

• jest.requireActual

[sheremet-va]

Since there's vi.importActual, could you please clarify plans to support jest plugins that use:

• jest.requireActual

No plans to support requireActual.

[sheremet-va]

You can use test.sequence.setupFiles: "list" to run setup files one after another. The hack with global.jest on the first line will stop working once Vite 4.3 is released as it will follow ESM spec for import hoisting.