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https://github.com/antfu/eslint-vitest-rule-tester

ESLint rule tester with Vitest, with more powerful and friendly APIs.
https://github.com/antfu/eslint-vitest-rule-tester

Last synced: about 1 month ago
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ESLint rule tester with Vitest, with more powerful and friendly APIs.

Host: GitHub
URL: https://github.com/antfu/eslint-vitest-rule-tester
Owner: antfu
License: mit
Created: 2024-05-06T18:17:42.000Z (4 months ago)
Default Branch: main
Last Pushed: 2024-07-13T11:49:00.000Z (2 months ago)
Last Synced: 2024-07-13T13:29:22.415Z (2 months ago)
Language: TypeScript
Homepage:
Size: 271 KB
Stars: 30
Watchers: 2
Forks: 4
Open Issues: 0
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- Funding: .github/FUNDING.yml
- License: LICENSE

Awesome Lists containing this project

README

        # eslint-vitest-rule-tester

[![npm version][npm-version-src]][npm-version-href]

[![npm downloads][npm-downloads-src]][npm-downloads-href]

[![bundle][bundle-src]][bundle-href]

[![JSDocs][jsdocs-src]][jsdocs-href]

[![License][license-src]][license-href]

ESLint rule tester with Vitest.

Provides a better testing experience, supports snapshoting, and does not require `globals: true` in Vitest.

> This module requires ESLint v9.0+.

## Who is using?

- [ESLint Stylistic](https://github.com/eslint-stylistic/eslint-stylistic/blob/main/packages/eslint-plugin-js/rules/array-bracket-newline/array-bracket-newline.test.ts)

- [eslint-plugin-command](https://github.com/antfu/eslint-plugin-command/blob/main/src/commands/inline-arrow.test.ts)

- [eslint-plugin-antfu](https://github.com/antfu/eslint-plugin-antfu/blob/main/src/rules/consistent-list-newline.test.ts)

## Install

```bash

npm i -D eslint-vitest-rule-tester

```

## Usage

### Classical Usage

Simliar style to ESLint's `RuleTester` (test cases with implicit test suites)

```ts

import { run, runClassic } from 'eslint-vitest-rule-tester'

import { expect } from 'vitest'

// Classic RuleTester.run style

runClassic('rule-name', rule, {

  valid: [

    // ...

  ],

  invalid: [

    // ...

  ],

}, {

  parserOptions: {

    ecmaVersion: 2020,

    sourceType: 'module',

  },

})

// Or everyting-in-one-object style

run({

  name: 'rule-name',

  rule,

  parserOptions: {

    ecmaVersion: 2020,

    sourceType: 'module',

  },

  valid: [

    // test cases

  ],

  invalid: [

    // test cases

  ],

})

```

Feature Extensions

#### `output`

`output` field can be a function to do custom assertions. This would also be compatible with snapshot testing.

```ts

import { run, } from 'eslint-vitest-rule-tester'

import { expect } from 'vitest'

run({

  name: 'rule-name',

  rule,

  invalid: [

    {

      code: 'let foo = 1',

      output(output) {

        expect(output.slice(0, 3)).toBe('let')

        expect(output)

          .toMatchInlineSnapshot(`"const foo = 1;"`)

        // Any custom assertion...

      },

    },

  ],

})

```

#### `errors`

`errors` field can be a function to do custom assertion, same as `output`.

```ts

import { run } from 'eslint-vitest-rule-tester'

import { expect } from 'vitest'

run({

  name: 'rule-name',

  rule,

  invalid: [

    {

      code: 'let foo = 1',

      errors(errors) {

        expect(errors).toHaveLength(1)

        expect(errors.map(e => e.messageId))

          .toMatchInlineSnapshot(`["error-message-id"]`)

        // Any custom assertion...

      },

    },

  ],

})

```

#### `onResult` hook

`onResult` field can be a function to do custom assertions with the entire result object.

```ts

import { runClassic } from 'eslint-vitest-rule-tester'

import { expect } from 'vitest'

run({

  name: 'rule-name',

  rule,

  invalid: [

    'let foo = 1',

  ],

  onResult(testCase, result) {

    if (testCase.type === 'invalid')

      expect(result).toMatchSnapshot()

    // here you can't use `toMatchInlineSnapshot` because it's not in the test case

  },

})

```

### Explicit Test Suites

```ts

import { createRuleTester } from 'eslint-vitest-rule-tester'

import { describe, expect, it } from 'vitest'

describe('rule-name', () => {

  const { valid, invalid } = createRuleTester({

    name: 'rule-name',

    rule,

    configs: {

      // flat config options

      languageOptions: {

        parserOptions: {

          ecmaVersion: 2020,

          sourceType: 'module',

        },

      },

    }

  })

  it('valid case 1', () => {

    valid('const foo = 1')

  })

  it('invalid case 1 with snapshot', () => {

    const result = invalid({

      code: 'const foo = 1',

      errors: ['error-message-id'],

    })

    expect(result.output).toMatchSnapshot()

  })

})

```

## Sponsors



  

    

  



## License

[MIT](./LICENSE) License © 2024-PRESENT [Anthony Fu](https://github.com/antfu)

[npm-version-src]: https://img.shields.io/npm/v/eslint-vitest-rule-tester?style=flat&colorA=080f12&colorB=1fa669

[npm-version-href]: https://npmjs.com/package/eslint-vitest-rule-tester

[npm-downloads-src]: https://img.shields.io/npm/dm/eslint-vitest-rule-tester?style=flat&colorA=080f12&colorB=1fa669

[npm-downloads-href]: https://npmjs.com/package/eslint-vitest-rule-tester

[bundle-src]: https://img.shields.io/bundlephobia/minzip/eslint-vitest-rule-tester?style=flat&colorA=080f12&colorB=1fa669&label=minzip

[bundle-href]: https://bundlephobia.com/result?p=eslint-vitest-rule-tester

[license-src]: https://img.shields.io/github/license/antfu/eslint-vitest-rule-tester.svg?style=flat&colorA=080f12&colorB=1fa669

[license-href]: https://github.com/antfu/eslint-vitest-rule-tester/blob/main/LICENSE

[jsdocs-src]: https://img.shields.io/badge/jsdocs-reference-080f12?style=flat&colorA=080f12&colorB=1fa669

[jsdocs-href]: https://www.jsdocs.io/package/eslint-vitest-rule-tester