callstackincubator / react-native-harness

Jest-style tool for testing native behavior directly on devices

Bridge the testing gap: Jest-style tests in real native environments. Get the convenience of describe/it with full access to native modules.

Features

• Jest-Style Syntax, Native Power: Write familiar describe/it tests that run in real iOS and Android environments with full native module access.
• Best of Both Worlds: Unlike Jest (Node.js only) or Maestro (UI-based), get convenient test syntax AND native environment execution.
• Real Device, Simulator & Web Testing: Execute tests on iOS simulators, Android emulators, or in a browser (Web) — catch platform-specific issues Jest can't see.
• Native Module Testing: Test native modules, platform APIs, and device-specific functionality that's impossible with JavaScript-only runners.
• Familiar Test Structure: Use beforeEach, afterEach, describe, it, expect — all the testing patterns you know and love from Jest.
• Zero Configuration Setup: Drop-in replacement for your existing test workflow with TypeScript support and seamless CI/CD integration.

Quick Configuration Example

// rn-harness.config.mjs
import {
  androidPlatform,
  androidEmulator,
  physicalAndroidDevice,
} from '@react-native-harness/platform-android';
import {
  applePlatform,
  applePhysicalDevice,
  appleSimulator,
} from '@react-native-harness/platform-apple';

const config = {
  entryPoint: './src/main.tsx',
  appRegistryComponentName: 'MyApp',

  runners: [
    androidPlatform({
      name: 'android',
      device: androidEmulator('Pixel_8_API_35'),
      bundleId: 'com.myapp',
    }),
    applePlatform({
      name: 'ios',
      device: appleSimulator('iPhone 16 Pro Max', '18.0'),
      bundleId: 'com.myapp',
    }),
  ],
  defaultRunner: 'android',
};

export default config;

Documentation

The documentation is available at react-native-harness.dev. You can also use the following links to jump to specific topics:

• Quick Start
• Configuration (Metro port, plugins, timeouts, coverage, and more)
• Problem Statement
• Feature Comparison
• Running in CI/CD
• API Reference

Made with ❤️ at Callstack

react-native-harness is an open source project and will always remain free to use. If you think it's cool, please star it 🌟. Callstack is a group of React and React Native geeks, contact us at hello@callstack.com if you need any help with these or just want to say hi!

Like the project? ⚛️ Join the team who does amazing stuff for clients and drives React Native Open Source! 🔥