The Minimalist JavaScript Test Runner

Zero config. Zero dependencies. Blazing fast. Instant feedback for developers who want results without the bloat.

Installation • Quick Start • Features • API Reference • Contributing

💡 Motivation

Modern test runners are powerful but often come with heavy configuration, slow startup times, and massive dependency trees.

tesht.js strips away the complexity. It gives you instant startup, a clean API, and zero overhead. It's built for when you just need to write a test and run it—fast.

[!NOTE] Why tesht.js? The package names test and tesht are reserved/taken on npm, so we use tesht.js.

✨ Features

• ⚡️ Instant Startup: Boots in ~50ms. No waiting.
• 🛠️ Zero Config: Works immediately. No config files required.
• 📦 Lightweight: Zero dependencies. No bloat in your node_modules.
• 🧠 Async First: First-class support for async/await and Promises.
• 🎨 Beautiful: Clean, colorful terminal output with fail-fast options.
• 🔁 Watch Mode: Auto-rerun tests on file changes for rapid development.
• 🎯 Focused Testing: Use .only() and .skip() to control test execution.
• 🪝 Test Hooks: beforeEach and afterEach for setup and cleanup.
• ⏱️ Timeout Support: Configurable timeouts prevent hanging tests.

📦 Installation

[!IMPORTANT] Run the following command to install the package as a development dependency:

npm install tesht.js --save-dev

🚀 Quick Start

Here's how easy it is to get started:

import { test, expect } from 'tesht.js';

// 1. Write a test (e.g., math.test.js)
test('basic arithmetic', () => {
    expect(1 + 1).toBe(2);
});

// 2. Async works automatically
test('async operations', async () => {
    const result = await Promise.resolve('success');
    expect(result).toBe('success');
});

// 3. Use hooks for setup/cleanup
**Run it:**

```bash
npx tesht              # Run all tests
npx tesht --watch      # Watch mode

afterEach(() => { // Cleanup after each test });

// 4. Skip or focus tests test.skip('not ready yet', () => { // This test won't run });

test.only('focus on this', () => { // Only .only tests will run });

**Run it:**

```bash
npx tesht

📖 API Reference

Core Methods

| Method | Description | |--------|-------------| | test(name, fn, options?) | Registers a test case. fn can be async. | | test.skip(name, fn) | Skip this test. | | test.only(name, fn) | Only run this test (and other .only tests). |

CLI Commands

npx tesht              # Run all tests in current dir
npx tesht src/         # Run tests in specific dir
npx tesht --all        # Run all tests (disable fail-fast)
npx tesht --watch      # Watch mode - rerun on changes
npx tesht --plain      # CI-friendly output (no colors/unicode)
npx tesht --ci         # Alias for --plain
```timeout`: Test timeout in ms (default: 5000)
### Matchers

Tesht.js provides essential matchers for your assertions:

| Matcher | Description | Example |
| :--- | :--- | :--- |
| `.toBe(expected)` | Strict equality (`===`). | `expect(x).toBe(5)` |
| `.toEqual(expected)` | Deep equality for objects/arrays. | `expect(obj).toEqual({a:1})` |
| `.toBeTruthy()` | Asserts value is truthy. | `expect(x).toBeTruthy()` |
| `.toBeFalsy()` | Asserts value is falsy. | `expect(x).toBeFalsy()` |
| `.toBeNull()` | Asserts value is `null`. | `expect(x).toBeNull()` |
| `.toBeUndefined()` | Asserts value is `undefined`. | `expect(x).toBeUndefined()` |
| `.toContain(item)` | Array/string contains item. | `expect([1,2]).toContain(2)` |
| `.toHaveLength(n)` | Array/string has length `n`. | `expect([1,2]).toHaveLength(2)` |
| `.toBeGreaterThan(n)` | Number is greater than `n`. | `expect(5).toBeGreaterThan(3)` |
| `.toBeLessThan(n)` | Number is less than `n`. | `expect(3).toBeLessThan(5)` |
| `.toMatch(regex)` | String matches regex. | `expect('hi').toMatch(/h/)` |
| `.toThrow(msg?)` | Function throws an error. | `expect(fn).toThrow()` |
npx tesht           # Run all tests in current dir
npx tesht src/      # Run tests in specific dir
npx tesht --all     # Run all tests (disable fail-fast)

Matchers

Tesht.js provides essential matchers for your assertions:

| Matcher | Description | Example | | :--- | :--- | :--- | | .toBe(expected) | Strict equality (===). | expect(x).toBe(5) | | .toEqual(expected) | Deep equality for objects/arrays. | expect(obj).toEqual({a:1}) | | .toBeTruthy() | Asserts value is truthy. | expect(x).toBeTruthy() | | .toBeFalsy() | Asserts value is falsy. | expect(x).toBeFalsy() | | .toThrow(msg?) | Asserts function throws an error. | expect(fn).toThrow() |

🤝 Contributing

We welcome contributions! Please feel free to open issues or submit PRs.

📄 License

MIT License © 2026