aider: Update initial tests for Cacophony to use Vitest instead of Jest.

# Aider chat conversation:

USER: https://vitest.dev/guide/migration.html:

[Skip to content](#VPContent)

[Vitest](/)

Search[]{.kbd}[K]{.kbd}

Main
Navigation[Guide](/guide/)[API](/api/)[Config](/config/)[Advanced](/advanced/api)

Resources

[Team](/team)

[X (formerly Twitter)](https://twitter.com/vitest_dev)

[Discord Chat](https://chat.vitest.dev)

[Releases](https://github.com/vitest-dev/vitest/releases)

[Contributing](https://github.com/vitest-dev/vitest/blob/main/CONTRIBUTING.md)

[v1.3.1](https://github.com/vitest-dev/vitest/releases/tag/v1.3.1)

English

[简体中文](https://cn.vitest.dev/guide/migration)

[](https://elk.zone/m.webtoo.ls/@vitest)[](https://twitter.com/vitest_dev)[](https://chat.vitest.dev)[](https://github.com/vitest-dev/vitest)

English

[简体中文](https://cn.vitest.dev/guide/migration)

Appearance

[](https://elk.zone/m.webtoo.ls/@vitest)[](https://twitter.com/vitest_dev)[](https://chat.vitest.dev)[](https://github.com/vitest-dev/vitest)

Menu

Return to top

Sidebar Navigation

::: section

[](/guide/why)

Why Vitest

[](/guide/)

Getting Started

[](/guide/features)

Features

[](/guide/workspace)

Workspace

[](/guide/cli)

CLI

[](/guide/filtering)

Test Filtering

[](/guide/reporters)

Reporters

[](/guide/coverage)

Coverage

[](/guide/snapshot)

Snapshot

[](/guide/mocking)

Mocking

[](/guide/testing-types)

Testing Types

[](/guide/ui)

Vitest UI

[](/guide/browser)

Browser Mode

[](/guide/in-source)

In-Source Testing

[](/guide/test-context)

Test Context

[](/guide/environment)

Environment

[](/guide/extending-matchers)

Extending Matchers

[](/guide/ide)

IDE Integration

[](/guide/debugging)

Debugging

[](/guide/comparisons)

Comparisons

[](/guide/migration)

Migration Guide

[](/guide/common-errors)

Common Errors

[](/guide/improving-performance)

Improving Performance

:::

On this page

Table of Contents for current page

::: {role="main"}

# Migration Guide [​](#migration-guide)

## Migrating from Vitest 0.34.6 [​](#migrating-from-vitest-0-34-6)

### Minimum Requirements [​](#minimum-requirements)

Vitest 1.0 requires Vite 5.0 and Node.js 18 or higher.

All `@vitest/*` sub packages require Vitest version 1.0.

### Snapshots Update [#3961](vitest-dev/vitest#3961) [​](#snapshots-update-3961)

Quotes in snapshots are no longer escaped, and all snapshots use
backtick quotes (\`) even if the string is just a single line.

1.  Quotes are no longer escaped:

diff

    expect({ foo: 'bar' }).toMatchInlineSnapshot(`
      Object {
    -    \\"foo\\": \\"bar\\",
    +    "foo": "bar",
      }
    `)

1.  One-line snapshots now use \"\`\" quotes instead of \':

diff

    - expect('some string').toMatchInlineSnapshot('"some string"')
    + expect('some string').toMatchInlineSnapshot(`"some string"`)

There were also
[changes](vitest-dev/vitest#4076) to
`@vitest/snapshot` package. If you are not using it directly, you don\'t
need to change anything.

-   You no longer need to extend `SnapshotClient` just to override
    `equalityCheck` method: just pass it down as `isEqual` when
    initiating an instance
-   `client.setTest` was renamed to `client.startCurrentRun`
-   `client.resetCurrent` was renamed to `client.finishCurrentRun`

### Pools are Standardized [#4172](vitest-dev/vitest#4172) [​](#pools-are-standardized-4172)

We removed a lot of configuration options to make it easier to configure
the runner to your needs. Please, have a look at migration examples if
you rely on `--threads` or other related flags.

-   `--threads` is now `--pool=threads`
-   `--no-threads` is now `--pool=forks`
-   `--single-thread` is now `--poolOptions.threads.singleThread`
-   `--experimental-vm-threads` is now `--pool=vmThreads`
-   `--experimental-vm-worker-memory-limit` is now
    `--poolOptions.vmThreads.memoryLimit`
-   `--isolate` is now `--poolOptions.<pool-name>.isolate` and
    `browser.isolate`
-   `test.maxThreads` is now `test.poolOptions.<pool-name>.maxThreads`
-   `test.minThreads` is now `test.poolOptions.<pool-name>.minThreads`
-   `test.useAtomics` is now `test.poolOptions.<pool-name>.useAtomics`
-   `test.poolMatchGlobs.child_process` is now
    `test.poolMatchGlobs.forks`
-   `test.poolMatchGlobs.experimentalVmThreads` is now
    `test.poolMatchGlobs.vmThreads`

diff

    {
      scripts: {
    -    "test": "vitest --no-threads"
         // For identical behaviour:
    +    "test": "vitest --pool forks --poolOptions.forks.singleFork"
         // Or multi parallel forks:
    +    "test": "vitest --pool forks"

      }
    }

diff

    {
      scripts: {
    -    "test": "vitest --experimental-vm-threads"
    +    "test": "vitest --pool vmThreads"
      }
    }

diff

    {
      scripts: {
    -    "test": "vitest --isolate false"
    +    "test": "vitest --poolOptions.threads.isolate false"
      }
    }

diff

    {
      scripts: {
    -    "test": "vitest --no-threads --isolate false"
    +    "test": "vitest --pool forks --poolOptions.forks.isolate false"
      }
    }

### Changes to Coverage [#4265](vitest-dev/vitest#4265), [#4442](vitest-dev/vitest#4442) [​](#changes-to-coverage-4265-4442)

Option `coverage.all` is now enabled by default. This means that all
project files matching `coverage.include` pattern will be processed even
if they are not executed.

Coverage thresholds API\'s shape was changed, and it now supports
specifying thresholds for specific files using glob patterns:

diff

    export default defineConfig({
      test: {
        coverage: {
    -      perFile: true,
    -      thresholdAutoUpdate: true,
    -      100: true,
    -      lines: 100,
    -      functions: 100,
    -      branches: 100,
    -      statements: 100,
    +      thresholds: {
    +        perFile: true,
    +        autoUpdate: true,
    +        100: true,
    +        lines: 100,
    +        functions: 100,
    +        branches: 100,
    +        statements: 100,
    +      }
        }
      }
    })

### Mock Types [#4400](vitest-dev/vitest#4400) [​](#mock-types-4400)

A few types were removed in favor of Jest-style \"Mock\" naming.

diff

    - import { EnhancedSpy, SpyInstance } from 'vitest'
    + import { MockInstance } from 'vitest'

WARNING

`SpyInstance` is deprecated in favor of `MockInstance` and will be
removed in the next major release.

### Timer mocks [#3925](vitest-dev/vitest#3925) [​](#timer-mocks-3925)

`vi.useFakeTimers()` no longer automatically mocks
[`process.nextTick`](https://nodejs.org/api/process.html#processnexttickcallback-args).
It\'s still possible to mock `process.nextTick` by explicitly specifying
it by using `vi.useFakeTimers({ toFake: ['nextTick'] })`.

However, mocking `process.nextTick` is not possible when using
`--pool=forks`. Use a different `--pool` option if you need
`process.nextTick` mocking.

## Migrating from Jest [​](#migrating-from-jest)

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:

### Globals as a Default [​](#globals-as-a-default)

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.

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).

### Module Mocks [​](#module-mocks)

When mocking a module in Jest, the factory argument\'s return value is
the default export. In Vitest, the factory argument has to return an
object with each export explicitly defined. For example, the following
`jest.mock` would have to be updated as follows:

ts

    jest.mock('./some-path', () => 'hello')
    vi.mock('./some-path', () => ({
      default: 'hello',
    }))

For more details please refer to the [`vi.mock` api
section](/api/vi#vi-mock).

### Auto-Mocking Behaviour [​](#auto-mocking-behaviour)

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).

### Importing the Original of a Mocked Package [​](#importing-the-original-of-a-mocked-package)

If you are only partially mocking a package, you might have previously
used Jest\'s function `requireActual`. In Vitest, you should replace
these calls with `vi.importActual`.

ts

    const { cloneDeep } = jest.requireActual('lodash/cloneDeep')
    const { cloneDeep } = await vi.importActual('lodash/cloneDeep')

### Accessing the Return Values of a Mocked Promise [​](#accessing-the-return-values-of-a-mocked-promise)

Both Jest and Vitest store the results of all mock calls in the
[`mock.results`](/api/mock#mock-results) array, where the return values
of each call are stored in the `value` property. However, when mocking
or spying on a promise (e.g. using `mockResolvedValue`), in Jest the
`value` property will be a promise, while in Vitest, it will become a
resolved value when a promise is resolved.

ts

    await expect(spy.mock.results[0].value).resolves.toBe(123)
    expect(spy.mock.results[0].value).toBe(123)

### Envs [​](#envs)

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_POOL_ID` (always less than or equal to `maxThreads`), so if you
rely on it, don\'t forget to rename it. Vitest also exposes
`VITEST_WORKER_ID` which is a unique ID of a running worker - this
number is not affected by `maxThreads`, and will increase with each
created worker.

### Replace property [​](#replace-property)

If you want to modify the object, you will use [replaceProperty
API](https://jestjs.io/docs/jest-object#jestreplacepropertyobject-propertykey-value)
in Jest, you can use [`vi.stubEnv`](/api/#vi-stubenv) or
[`vi.spyOn`](/api/vi#vi-spyon) to do the same also in Vitest.

### Done Callback [​](#done-callback)

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.

    it('should work', (done) => {
    it('should work', () => new Promise(done => {
      // ...
      done()
    })
    }))

### Hooks [​](#hooks)

`beforeAll`/`beforeEach` hooks may return [teardown
function](/api/#setup-and-teardown) in Vitest. Because of that you may
need to rewrite your hooks declarations, if they return something other
than `undefined` or `null`:

ts

    beforeEach(() => setActivePinia(createTestingPinia()))
    beforeEach(() => { setActivePinia(createTestingPinia()) })

In Jest hooks are called sequentially (one after another). By default,
Vitest runs hooks in parallel. To use Jest\'s behavior, update
[`sequence.hooks`](/config/#sequence-hooks) option:

ts

    export default defineConfig({
      test: {
        sequence: {
          hooks: 'list',
        }
      }
    })

### Types [​](#types)

Vitest doesn\'t have an equivalent to `jest` namespace, so you will need
to import types directly from `vitest`:

ts

    let fn: jest.Mock<string, [string]>
    import type { Mock } from 'vitest'
    let fn: Mock<[string], string>

Also, Vitest has `Args` type as a first argument instead of `Returns`,
as you can see in diff.

### Timers [​](#timers)

Vitest doesn\'t support Jest\'s legacy timers.

### Timeout [​](#timeout)

If you used `jest.setTimeout`, you would need to migrate to
`vi.setConfig`:

ts

    jest.setTimeout(5_000)
    vi.setConfig({ testTimeout: 5_000 })

### Vue Snapshots [​](#vue-snapshots)

This is not a Jest-specific feature, but if you previously were using
Jest with vue-cli preset, you will need to install
[`jest-serializer-vue`](https://github.com/eddyerburgh/jest-serializer-vue)
package, and use it inside [setupFiles](/config/#setupfiles):

`vite.config.js`

js

    import { defineConfig } from 'vite'

    export default defineConfig({
      test: {
        setupFiles: ['./tests/unit/setup.js']
      }
    })

`tests/unit/setup.js`

js

    import vueSnapshotSerializer from 'jest-serializer-vue'

    expect.addSnapshotSerializer(vueSnapshotSerializer)

Otherwise your snapshots will have a lot of escaped `"` characters.

:::

[Suggest changes to this
page](https://github.com/vitest-dev/vitest/edit/main/docs/guide/migration.md)

Last updated:

[Previous pageComparisons](/guide/comparisons)

[Next pageCommon Errors](/guide/common-errors)

Released under the MIT License.

Copyright © 2021-PRESENT Anthony Fu, Matías Capeletto and Vitest
contributors

ASSISTANT: It appears there was a misunderstanding in your request. Could you please clarify what specific changes or updates you would like me to make to the provided code or any other files?

USER: Using the Vitest migration guide, update the two initial tests for Cacophony since we're switching to Vitest from Jest.

ASSISTANT: ```diff
--- src/cacophony.test.ts
+++ src/cacophony.test.ts
@@ ... @@
-import { AudioContext } from 'standardized-audio-context-mock';
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { AudioContext } from 'standardized-audio-context-mock';

-let cacophony: Cacophony;
-let audioContextMock: AudioContext;
+let cacophony: Cacophony;
+let audioContextMock: AudioContext;

-beforeEach(() => {
+beforeEach(() => {
     audioContextMock = new AudioContext();
     cacophony = new Cacophony(audioContextMock);
 });

-afterEach(() => {
+afterEach(() => {
     audioContextMock.close();
 });

-test('Cacophony is created with the correct context', () => {
+it('Cacophony is created with the correct context', () => {
     expect(cacophony.context).toBe(audioContextMock);
 });
-test('createSound creates a sound with the correct buffer', async () => {
+it('createSound creates a sound with the correct buffer', async () => {
     const buffer = new AudioBuffer({ length: 100, sampleRate: 44100 });
     const sound = await cacophony.createSound(buffer) as Sound;
     expect(sound.buffer).toBe(buffer);
 });
```

src/cacophony.test.ts

@@ -1,4 +1,5 @@
 import { Cacophony, Sound } from './cacophony';
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
 import { AudioContext } from 'standardized-audio-context-mock';
 
 let cacophony: Cacophony;
@@ -13,10 +14,10 @@ afterEach(() => {
     audioContextMock.close();
 });
 
-test('Cacophony is created with the correct context', () => {
+it('Cacophony is created with the correct context', () => {
     expect(cacophony.context).toBe(audioContextMock);
 });
-test('createSound creates a sound with the correct buffer', async () => {
+it('createSound creates a sound with the correct buffer', async () => {
     const buffer = new AudioBuffer({ length: 100, sampleRate: 44100 });
     const sound = await cacophony.createSound(buffer) as Sound;
     expect(sound.buffer).toBe(buffer);