bun-test

Bun Test Configuration

Set up Bun's built-in test runner with Jest-compatible APIs and significantly faster execution (3-10x faster than Jest).

Quick Reference

For detailed patterns, see:

• Jest Migration: jest-migration.md - Complete Jest to Bun migration guide
• Mocking: mocking.md - Mock functions, spies, module mocking
• Examples: examples.md - Test patterns for APIs, databases, async code

Core Workflow

1. Check Prerequisites

# Verify Bun installation
bun --version

# Check if project exists
ls -la package.json

2. Determine Testing Needs

Ask the user what type of testing they need:

• Unit Testing: Test individual functions and modules
• Integration Testing: Test component interactions
• API Testing: Test HTTP endpoints
• Snapshot Testing: Test output consistency

3. Create Test Directory Structure

# Create test directories
mkdir -p tests/{unit,integration,fixtures}

Recommended structure:

project/
├── src/
│   ├── utils.ts
│   └── components/
├── tests/
│   ├── unit/              # Unit tests
│   ├── integration/       # Integration tests
│   ├── fixtures/          # Test data
│   └── setup.ts          # Global setup
├── package.json
└── bunfig.toml           # Test configuration

4. Configure Bun Test

Create bunfig.toml in project root:

[test]
# Preload files before running tests
preload = ["./tests/setup.ts"]

# Code coverage
coverage = true
coverageDir = "coverage"
coverageThreshold = 80

# Timeouts (in milliseconds)
timeout = 5000

# Bail after first failure
bail = false

5. Create Test Setup File

Create tests/setup.ts:

import { beforeAll, afterAll, beforeEach, afterEach } from "bun:test";

// Global test setup
beforeAll(() => {
  console.log("🧪 Starting test suite");
  process.env.NODE_ENV = "test";
});

afterAll(() => {
  console.log("✅ Test suite complete");
});

// Reset mocks before each test
beforeEach(() => {
  // Clear mock state
});

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

// Global test utilities
globalThis.testHelpers = {
  wait: (ms: number) => new Promise(resolve => setTimeout(resolve, ms)),
};