eslint-plugin-vitest

ESLint plugin for Vitest

Installation

You'll first need to install ESLint:

npm i eslint --save-dev

Next, install @vitest/eslint-plugin

npm install @vitest/eslint-plugin --save-dev

Usage

Make sure you're running ESLint v9.0.0 or higher for the latest version of this plugin to work. The following example is how your eslint.config.js should be setup for this plugin to work for you.

import { defineConfig } from 'eslint/config'
import vitest from '@vitest/eslint-plugin'

export default defineConfig({
  files: ['tests/**'], // or any other pattern
  plugins: {
    vitest,
  },
  rules: {
    ...vitest.configs.recommended.rules, // you can also use vitest.configs.all.rules to enable all rules
    'vitest/max-nested-describe': ['error', { max: 3 }], // you can also modify rules' behavior using option like this
  },
})

If you're not using the latest version of ESLint (version v8.57.0 or lower) you can setup this plugin using the following configuration

Add vitest to the plugins section of your .eslintrc configuration file. You can omit the eslint-plugin- prefix:

{
  "plugins": ["@vitest"]
}

Then configure the rules you want to use under the rules section.

{
  "rules": {
    "@vitest/max-nested-describe": [
      "error",
      {
        "max": 3
      }
    ]
  }
}

If you're using old ESLint configuration, make sure to use legacy key like the following

{
  "extends": ["plugin:@vitest/legacy-recommended"] // or legacy-all
}

Enabling with Type-Testing

Vitest ships with an optional type-testing feature, which is disabled by default.

If you're using this feature, you should also enabled typecheck in the settings for this plugin. This ensures that rules like expect-expect account for type-related assertions in tests.

import { defineConfig } from 'eslint/config'
import tseslint from 'typescript-eslint'
import vitest from '@vitest/eslint-plugin'

export default defineConfig(
  // see https://typescript-eslint.io
  tseslint.configs.recommended,
  {
    languageOptions: {
      parserOptions: {
        projectService: true,
      },
    },
  },
  {
    files: ['tests/**'], // or any other pattern
    plugins: {
      vitest,
    },
    rules: {
      ...vitest.configs.recommended.rules,
    },
    settings: {
      vitest: {
        typecheck: true,
      },
    },
    languageOptions: {
      globals: {
        ...vitest.environments.env.globals,
      },
    },
  },
)

Custom Fixtures

If you're using custom fixtures in a separate file and importing them in your tests, you can let the plugin know about them by adding them to the vitestImports setting. The property accepts an array of strings or regular expressions that match the module names where your custom fixtures are defined.

import { defineConfig } from 'eslint/config'
import vitest from '@vitest/eslint-plugin'

export default defineConfig({
  files: ['tests/**'], // or any other pattern
  plugins: {
    vitest,
  },
  rules: {
    ...vitest.configs.recommended.rules,
  },
  settings: {
    vitest: {
      vitestImports: ['@/tests/fixtures', /test-extend$/],
    },
  },
})

Shareable Configurations

Recommended

This plugin exports a recommended configuration that enforces good testing practices.

To enable this configuration with eslint.config.js, use vitest.configs.recommended:

import { defineConfig } from 'eslint/config'
import vitest from '@vitest/eslint-plugin'

export default defineConfig({
  files: ['tests/**'], // or any other pattern
  ...vitest.configs.recommended,
})

All

If you want to enable all rules instead of only some you can do so by adding the all configuration to your eslint.config.js config file:

import { defineConfig } from 'eslint/config'
import vitest from '@vitest/eslint-plugin'

export default defineConfig({
  files: ['tests/**'], // or any other pattern
  ...vitest.configs.all,
})

Rules

💼 Configurations enabled in.
⚠️ Configurations set to warn in.
🚫 Configurations disabled in.
🌐 Set in the all configuration.
✅ Set in the recommended configuration.
🔧 Automatically fixable by the --fix CLI option.
💡 Manually fixable by editor suggestions.
💭 Requires type information.
❌ Deprecated.

Name	Description	💼	⚠️	🚫	🔧	💡	💭	❌
consistent-each-for	enforce using .each or .for consistently		🌐
consistent-test-filename	require test file pattern		🌐
consistent-test-it	enforce using test or it but not both		🌐		🔧
consistent-vitest-vi	enforce using vitest or vi but not both		🌐		🔧
expect-expect	enforce having expectation in test body	✅	🌐
hoisted-apis-on-top	enforce hoisted APIs to be on top of the file		🌐			💡
max-expects	enforce a maximum number of expect per test		🌐
max-nested-describe	require describe block to be less than set max value or default value		🌐
no-alias-methods	disallow alias methods		🌐		🔧
no-commented-out-tests	disallow commented out tests	✅	🌐
no-conditional-expect	disallow conditional expects	✅	🌐
no-conditional-in-test	disallow conditional tests		🌐
no-conditional-tests	disallow conditional tests		🌐
no-disabled-tests	disallow disabled tests		🌐 ✅
no-done-callback	disallow using a callback in asynchronous tests and hooks					💡		❌
no-duplicate-hooks	disallow duplicate hooks and teardown hooks		🌐
no-focused-tests	disallow focused tests	✅	🌐		🔧
no-hooks	disallow setup and teardown hooks		🌐
no-identical-title	disallow identical titles	✅	🌐		🔧
no-import-node-test	disallow importing node:test	✅	🌐		🔧
no-importing-vitest-globals	disallow importing Vitest globals			🌐	🔧
no-interpolation-in-snapshots	disallow string interpolation in snapshots	✅	🌐		🔧
no-large-snapshots	disallow large snapshots		🌐
no-mocks-import	disallow importing from mocks directory	✅	🌐
no-restricted-matchers	disallow the use of certain matchers		🌐
no-restricted-vi-methods	disallow specific vi. methods		🌐
no-standalone-expect	disallow using expect outside of it or test blocks	✅	🌐
no-test-prefixes	disallow using the f and x prefixes in favour of .only and .skip		🌐		🔧
no-test-return-statement	disallow return statements in tests		🌐
no-unneeded-async-expect-function	Disallow unnecessary async function wrapper for expected promises	✅	🌐		🔧
padding-around-after-all-blocks	Enforce padding around afterAll blocks		🌐		🔧
padding-around-after-each-blocks	Enforce padding around afterEach blocks		🌐		🔧
padding-around-all	Enforce padding around vitest functions		🌐		🔧
padding-around-before-all-blocks	Enforce padding around beforeAll blocks		🌐		🔧
padding-around-before-each-blocks	Enforce padding around beforeEach blocks		🌐		🔧
padding-around-describe-blocks	Enforce padding around describe blocks		🌐		🔧
padding-around-expect-groups	Enforce padding around expect groups		🌐		🔧
padding-around-test-blocks	Enforce padding around test blocks		🌐		🔧
prefer-called-exactly-once-with	Prefer toHaveBeenCalledExactlyOnceWith over toHaveBeenCalledOnce and toHaveBeenCalledWith	✅	🌐		🔧
prefer-called-once	enforce using toBeCalledOnce() or toHaveBeenCalledOnce()			🌐	🔧
prefer-called-times	enforce using toBeCalledTimes(1) or toHaveBeenCalledTimes(1)		🌐		🔧
prefer-called-with	enforce using toBeCalledWith() or toHaveBeenCalledWith()		🌐		🔧
prefer-comparison-matcher	enforce using the built-in comparison matchers		🌐		🔧
prefer-describe-function-title	enforce using a function as a describe title over an equivalent string		🌐		🔧
prefer-each	enforce using each rather than manual loops		🌐
prefer-equality-matcher	enforce using the built-in equality matchers		🌐			💡
prefer-expect-assertions	enforce using expect assertions instead of callbacks		🌐			💡
prefer-expect-resolves	enforce using expect().resolves over expect(await ...) syntax		🌐		🔧
prefer-expect-type-of	enforce using expectTypeOf instead of expect(typeof ...)		🌐		🔧
prefer-hooks-in-order	enforce having hooks in consistent order		🌐
prefer-hooks-on-top	enforce having hooks before any test cases		🌐
prefer-import-in-mock	prefer dynamic import in mock		🌐		🔧
prefer-importing-vitest-globals	enforce importing Vitest globals		🌐		🔧
prefer-lowercase-title	enforce lowercase titles		🌐		🔧
prefer-mock-promise-shorthand	enforce mock resolved/rejected shorthands for promises		🌐		🔧
prefer-mock-return-shorthand	Prefer mock return shorthands				🔧
prefer-snapshot-hint	enforce including a hint with external snapshots		🌐
prefer-spy-on	enforce using vi.spyOn		🌐		🔧
prefer-strict-boolean-matchers	enforce using toBe(true) and toBe(false) over matchers that coerce types to boolean		🌐		🔧
prefer-strict-equal	enforce strict equal over equal		🌐			💡
prefer-to-be	enforce using toBe()		🌐		🔧
prefer-to-be-falsy	enforce using toBeFalsy()			🌐	🔧
prefer-to-be-object	enforce using toBeObject()		🌐		🔧
prefer-to-be-truthy	enforce using toBeTruthy			🌐	🔧
prefer-to-contain	enforce using toContain()		🌐		🔧
prefer-to-have-been-called-times	Suggest using toHaveBeenCalledTimes()		🌐		🔧
prefer-to-have-length	enforce using toHaveLength()		🌐		🔧
prefer-todo	enforce using test.todo		🌐		🔧
prefer-vi-mocked	require vi.mocked() over fn as Mock		🌐		🔧		💭
require-awaited-expect-poll	ensure that every expect.poll call is awaited		🌐
require-hook	require setup and teardown to be within a hook		🌐
require-local-test-context-for-concurrent-snapshots	require local Test Context for concurrent snapshot tests	✅	🌐
require-mock-type-parameters	enforce using type parameters with vitest mock functions		🌐		🔧
require-test-timeout	require tests to declare a timeout			🌐
require-to-throw-message	require toThrow() to be called with an error message		🌐
require-top-level-describe	enforce that all tests are in a top-level describe		🌐
unbound-method	enforce unbound methods are called with their expected scope		🌐				💭
valid-describe-callback	enforce valid describe callback	✅	🌐
valid-expect	enforce valid expect() usage	✅	🌐		🔧
valid-expect-in-promise	require promises that have expectations in their chain to be valid	✅	🌐
valid-title	enforce valid titles	✅	🌐		🔧
warn-todo	disallow .todo usage

Credits

• eslint-plugin-jest: most of the rules in this plugin are essentially ports of Jest plugin rules with minor modifications

Licence

MIT Licence © 2022 - present by veritem and contributors