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4f198ef284
* feat: support concurrent snapshot * feat: cleanup callback for `beforeAll` and `beforeEach`
41 lines
2.0 KiB
Markdown
41 lines
2.0 KiB
Markdown
# Migration Guide
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## Migrating from Jest
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Vitest has been designed with a Jest compatible API, in order to make the migration from Jest as simple as possible. Despite those efforts, you may still run into the following differences:
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**Globals as a Default**
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Jest has their [globals API](https://jestjs.io/docs/api) enabled by default. Vitest does not. You can either enable globals via [the `globals` configuration setting](/config/#globals) or update your code to use imports from the `vitest` module instead.
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If you decide to keep globals disabled, be aware that common libraries like [`testing-library`](https://testing-library.com/) will not run auto DOM [cleanup](https://testing-library.com/docs/svelte-testing-library/api/#cleanup).
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**Auto-Mocking Behaviour**
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Unlike Jest, mocked modules in `<root>/__mocks__` are not loaded unless `vi.mock()` is called. If you need them to be mocked in every test, like in Jest, you can mock them inside [`setupFiles`](/config/#setupfiles).
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**Mocking globals**
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In Jest, you could mock global variables by putting them on `window` object. Vitest treats `globalThis` and `window` as different objects, so you would need to either put it on both `window` and `globalThis`, or use [`vi.stubGlobal`](/api/#vi-stubglobal) helper.
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**Jasmine API**
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Jest exports various [`jasmine`](https://jasmine.github.io/) globals (such as `jasmine.any()`). Any such instances will need to be migrated to [their Vitest counterparts](/api/).
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**Envs**
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Just like Jest, Vitest sets `NODE_ENV` to `test`, if it wasn't set before. Vitest also has a counterpart for `JEST_WORKER_ID` called `VITEST_WORKER_ID`, so if you rely on it, don't forget to rename it.
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**Done Callback**
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From Vitest v0.10.0, the callback style of declaring tests is deprecated. You can rewrite them to use `async`/`await` functions, or use Promise to mimic the callback style.
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```diff
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- it('should work', (done) => {
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+ it('should work', () => new Promise(done => {
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// ...
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done()
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- })
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+ }))
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```
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