Yeoman Compatibility Testing

This project contains a comprehensive test suite for testing Yeoman generator compatibility across different versions of yeoman-generator and yo CLI, with both CommonJS (CJS) and ES Modules (ESM/MJS) implementations.

Project Structure

yeoman-compat-testing/
├── generators/          # Test generators
│   ├── generator-gen5-cjs/    # CommonJS generator using yeoman-generator v5
│   ├── generator-gen5-mjs/    # ESM generator using yeoman-generator v5
│   ├── generator-gen6-cjs/    # CommonJS generator using yeoman-generator v6
│   ├── generator-gen6-mjs/    # ESM generator using yeoman-generator v6
│   ├── generator-gen7-cjs/    # CommonJS generator using yeoman-generator v7
│   └── generator-gen7-mjs/    # ESM generator using yeoman-generator v7
├── scenarios/          # Test scenario documentation
├── scripts/           # Automation scripts
│   ├── yeoman-scaffold.sh    # Script to generate all test generators
│   └── yeoman-test.sh        # Script to run all compatibility tests
└── README.md          # This file

Generators Overview

Each generator tests a specific combination of:

• Module System: CommonJS (CJS) vs ES Modules (MJS)
• yeoman-generator Version: v5, v6, or v7

Generator	Module System	yeoman-generator Version	Output File
generator-gen5-cjs	CommonJS	^5.0.0	cjs-output.txt
generator-gen5-mjs	ES Modules	^5.0.0	esm-output.txt
generator-gen6-cjs	CommonJS	^6.0.0	cjs-output.txt
generator-gen6-mjs	ES Modules	^6.0.0	esm-output.txt
generator-gen7-cjs	CommonJS	^7.0.0	cjs-output.txt
generator-gen7-mjs	ES Modules	^7.0.0	esm-output.txt

Prerequisites

• Node.js (recommended: latest LTS version)
• npm
• Global access to install packages (for npm link)

Quick Start

Option 1: Run All Tests Automatically

Use the provided test script to run all compatibility tests:

# Make sure you're in the project root
cd /path/to/yeoman-compat-testing

# Run all compatibility tests
./scripts/yeoman-test.sh

This script will:

• Test each generator with multiple yo CLI versions (4.3.1, 5.1.0, 6.0.0)
• Automatically link/unlink generators
• Display colored output showing success/failure status

Option 2: Run Individual Generators

To test a specific generator manually:

# 1. Navigate to the generator directory
cd generators/generator-gen7-mjs

# 2. Install dependencies
npm install --legacy-peer-deps

# 3. Link the generator globally
npm link

# 4. Run the generator with a specific yo version
npx -y -p yo@6.0.0 -- yo generator-gen7-mjs

# 5. Clean up - unlink the generator
npm unlink -g generator-gen7-mjs

Option 3: Test Against Different yo Versions

You can test any generator against different yo CLI versions:

# Test with yo v4.3.1
npx -y -p yo@4.3.1 -- yo generator-gen7-mjs

# Test with yo v5.1.0
npx -y -p yo@5.1.0 -- yo generator-gen7-mjs

# Test with yo v6.0.0
npx -y -p yo@6.0.0 -- yo generator-gen7-mjs

Understanding the Test Results

Successful Run

When a generator runs successfully, you should see:

• Console output: "Hello from CJS generator!" or "Hello from ESM generator!"
• Exit code: 0

Common Issues

• Module resolution errors: Often indicate compatibility issues between yeoman-generator versions and yo CLI versions
• Import/export errors: May indicate ES Module compatibility problems
• Dependency conflicts: Resolved by using --legacy-peer-deps flag

Generator Implementation Details

CommonJS Generators (CJS)

const Generator = require('yeoman-generator');

module.exports = class extends Generator {
  writing() {
    this.log("Hello from CJS generator!");
    this.fs.write(this.destinationPath("cjs-output.txt"), "Generated by CJS");
  }
};

ES Module Generators (MJS)

import Generator from 'yeoman-generator';

export default class extends Generator {
  writing() {
    this.log("Hello from ESM generator!");
    this.fs.write(this.destinationPath("esm-output.txt"), "Generated by ESM");
  }
}

Compatibility Matrix

Based on actual test results, here are the compatibility outcomes:

Generator Version	yo v4.3.1	yo v5.1.0	yo v6.0.0
gen5-cjs	✅	✅	✅
gen5-mjs	✅	✅	✅
gen6-cjs	❌	❌	❌
gen6-mjs	✅	✅	✅
gen7-cjs	❌	❌	❌
gen7-mjs	❌	✅	✅

Key Findings

✅ Fully Compatible:

• gen5-cjs & gen5-mjs: yeoman-generator v5 works perfectly with all yo CLI versions
• gen6-mjs: yeoman-generator v6 ESM works with all yo CLI versions

⚠️ Partially Compatible:

• gen7-mjs: yeoman-generator v7 ESM only works with yo v5.1.0+ (requires yeoman-environment 4.0.0+)

❌ Incompatible:

• gen6-cjs & gen7-cjs: CommonJS generators fail with yeoman-generator v6+ due to module resolution issues

Error Analysis

1. gen6-cjs & gen7-cjs failures:

   • Error: Class extends value [object Module] is not a constructor or null
   • Cause: Module resolution conflicts between CommonJS and newer yeoman-generator versions

2. gen7-mjs with yo@4.3.1 failure:

   • Error: This generator requires yeoman-environment at least 4.0.0-rc.0, current version is 3.19.3
   • Cause: yeoman-generator v7 requires newer yeoman-environment than what yo@4.3.1 provides

Recommendations

• For maximum compatibility: Use yeoman-generator v5 with either CommonJS or ES Modules
• For ES Modules: yeoman-generator v6+ works well, but avoid CommonJS with these versions
• For latest features: Use yeoman-generator v7 with yo v5.1.0+ and ES Modules only