lightningimg/TESTING.md

A blazing fast, transparent, and safe image converter powered by WebAssembly. Convert PNG, JPG, TIFF, and GIF images to optimized WebP format with high performance and cross-platform compatibility.

# 🧪 LightningImg Testing Suite

This document describes the comprehensive testing setup for the LightningImg WASM-only ESM implementation.

## 📋 Available Tests

### 1. **ESM Node.js Test** (`test:esm`)
- **File**: `test-esm.js`
- **Purpose**: Tests the WASM module in Node.js environment
- **Features**:
  - Loads actual image files from `test_images/`
  - Tests all core functions: `getImageInfo`, `convertImageBuffer`, `isSupportedFormat`
  - Uses Node.js WASM target (`pkg-node/`)
  - Validates real-world image conversion scenarios

### 2. **Browser Puppeteer Test** (`test:browser`)
- **File**: `test-browser-puppeteer.js` + `browser-test-simple.html`
- **Purpose**: Automated browser testing using Puppeteer
- **Features**:
  - Creates test images using Canvas API
  - Tests WASM module in real browser environment
  - Uses web WASM target (`pkg/`)
  - Validates browser-specific scenarios (CORS, ES modules, etc.)
  - Includes HTTP server for proper WASM loading
  - Takes screenshots for debugging
  - Comprehensive logging and error handling

### 3. **WASM Unit Tests** (`test:wasm`)
- **Location**: `lightningimg-wasm/` directory
- **Purpose**: Tests the underlying Rust WASM code
- **Features**: Rust-level unit tests and WASM binding validation

## 🚀 Running Tests

```bash
# Run all tests (ESM + Browser)
pnpm test

# Run individual tests
pnpm run test:esm      # Node.js ESM test
pnpm run test:browser  # Puppeteer browser test
pnpm run test:wasm     # WASM unit tests

# Run examples
pnpm run example:simple  # Simple Node.js example
```

## 📊 Test Results Summary

### Node.js Environment (ESM Test)
- ✅ WASM module loading
- ✅ Image info extraction
- ✅ Format validation
- ✅ Image conversion (PNG → WebP)
- ✅ File I/O operations

### Browser Environment (Puppeteer Test)
- ✅ WASM module loading via ES modules
- ✅ Canvas API image generation
- ✅ Dynamic imports working
- ✅ All core functions operational
- ✅ Excellent compression ratios (~71% for test images)
- ✅ Cross-browser compatibility (via Chromium)

## 🔧 Technical Details

### Browser Test Architecture
1. **HTTP Server**: Custom server for proper MIME types and CORS headers
2. **Canvas Generation**: Creates test images dynamically in browser
3. **Puppeteer Integration**: Automated browser control and result collection
4. **Environment Detection**: Automatically loads correct WASM target

### Test Coverage
- ✅ Module loading in both Node.js and browser
- ✅ All exported functions (`convertImageBuffer` with resize support, `getImageInfo`, `isSupportedFormat`)
- ✅ Error handling and edge cases
- ✅ Performance metrics and compression ratios
- ✅ Real-world image processing scenarios

## 📁 Test Files

```
test-esm.js                    # Node.js ESM test
test-browser-puppeteer.js      # Puppeteer browser test runner
browser-test-simple.html       # Browser test page
browser-example.html           # Interactive browser demo
example-simple.js              # Simple usage example
test_images/                   # Test image assets
  ├── defuss_logo_png.png
  ├── defuss_logo_jpg.jpg
  └── defuss_logo_tiff.tiff
```

## 🎯 Success Criteria

Both tests validate:
- ✅ ESM module system compatibility
- ✅ WASM loading and initialization
- ✅ Cross-environment functionality (Node.js + Browser)
- ✅ Image conversion accuracy
- ✅ Performance and compression quality
- ✅ Error handling and edge cases

The testing suite ensures the LightningImg WASM-only implementation works reliably across all target environments with consistent API behavior.