Below is a clear and complete guide on the Node.js Test Runner, introduced officially in Node.js v18+ as a built-in testing framework — no external packages required.

🚀 Node.js Test Runner (Built-in Testing Framework)

Node.js now includes a native test runner so you can write tests without Jest, Mocha, or any other library.

Import from:

Or using ES Modules:

⭐ 1. Create Your First Node.js Test

📁 sum.js

📁 sum.test.js

Run test:

⭐ 2. Asynchronous Tests

Supports async/await:

⭐ 3. Test Suites (Subtests)

Use nested tests:

⭐ 4. Running a Specific Test File

⭐ 5. Using Test Hooks (Before / After)

⭐ 6. Skipping Tests

⭐ 7. Todo Tests

⭐ 8. Mocking & Spying (built-in)

Node.js has its own mocking API:

⭐ 9. Test Reporter Options

To see full output:

Available reporters:

• tap

• spec

• json

• junit

Example:

⭐ 10. Assertions API

Node.js Test Runner uses node:assert, including:

Example:

⭐ 11. Testing ES Modules

Run:

⭐ 12. Folder Structure

Node automatically detects files named:

• *.test.js

• test-*.js

• inside /test folder

⭐ 13. Comparison: Node Test Runner vs Jest vs Mocha

🎯 When to Use Node.js Test Runner?

Use it when:

✔ You want minimal dependencies
✔ You want very fast tests
✔ You work mostly on backend / APIs
✔ You prefer native Node.js tools
✔ You don’t need React/Jest-specific features