rstest

Rstest

Rstest is a testing framework powered by Rspack. It provides Jest-compatible APIs with native TypeScript and ESM support, and integrates directly into the Rstack toolchain (Rspack, Rsbuild, Rslib, Rspress).

Key things that distinguish Rstest from Jest/Vitest:

• Build tooling is Rspack, not Babel or Vite — it reuses your existing Rsbuild/Rspack config
• Two separate utility namespaces: rs for module-level operations (mocking modules), and rstest for runtime utilities (fn, spyOn, timers). Both are imported from @rstest/core
• rs.mock() without a factory is NOT auto-mock — it looks for __mocks__/ directory only. For auto-mocking, pass { mock: true }. This is the biggest gotcha when migrating from Vitest
• Mock factories cannot be async — use import ... with { rstest: 'importActual' } for partial mocks instead
• No --run flag — rstest already runs once and exits. Use rstest --watch or rstest watch for watch mode
• Node.js ≥ 20.19.0 required

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Setup

Install

# npm / pnpm / yarn / bun
pnpm add @rstest/core -D

package.json scripts

{
  "scripts": {
    "test": "rstest",
    "test:watch": "rstest watch"
  }
}

Configuration file

Rstest auto-discovers config files in the project root in this order: rstest.config.mjs, .ts, .js, .cjs, .mts, .cts.

// rstest.config.ts
import { defineConfig } from '@rstest/core';

export default defineConfig({
  // Test config is at the top level — NOT nested under a `test` key (unlike Vitest)
  include: ['**/*.{test,spec}.?(c|m)[jt]s?(x)'],
  exclude: ['**/node_modules/**', '**/dist/**'],
  testEnvironment: 'node', // 'node' | 'jsdom' | 'happy-dom'
  globals: false,          // set true to skip imports in test files
  setupFiles: [],          // runs before each test file
  testTimeout: 5000,
  retry: 0,
});

If your project already uses Rsbuild or Rslib, use the official adapters to avoid config duplication — see "Rsbuild / Rslib integration" below.