eslint-bun-rule-tester

Explicit, type-safe ESLint rule testing with Bun.

Install

bun add --dev eslint-bun-rule-tester eslint

Usage

import { test } from 'bun:test'
import { createRuleTester } from 'eslint-bun-rule-tester'
import { rule } from './rule.ts'

const { invalid, valid } = createRuleTester({
  name: 'my-rule',
  rule,
})

test('accepts valid code', () => {
  valid('const value = true')
})

test('reports invalid code', () => {
  invalid({
    code: 'const value = false',
    errors: ['invalidValue'],
  })
})

String error assertions are inferred from rule.meta.messages. The tester also accepts partial ESLint diagnostics, filenames, working directories, default rule options, per-case rule options, and custom language options.

This package executes rules with ESLint's Linter. ESLint-compatible rules intended for another runtime, including Oxlint JS plugins, still need an integration test in that runtime.

API

createRuleTester(options)

Returns explicit valid(testCase) and invalid(testCase) assertion functions for use inside Bun tests. A valid case may be a source string or an object. Invalid cases require an error count or expected diagnostics.

License

MIT