Parallel Testing in Angular using Karma

This project is configured to run parallel tests in an Angular application using Karma and the karma-parallel plugin.

Prerequisites

Ensure you have the following installed:

• Node.js (Latest LTS recommended)
• Angular CLI
• Chrome browser

Installation

Clone the repository and install dependencies:

npm install

Configuration

The Karma configuration (karma.conf.js) includes the karma-parallel plugin for running tests in parallel. The key configurations are:

parallelOptions: {
  executors: 4, // Defaults to cpu-count - 1
  shardStrategy: 'round-robin'
},

browsers: ['ChromeHeadlessNoSandbox'],
customLaunchers: {
  ChromeHeadlessNoSandbox: {
    base: 'ChromeHeadless',
    flags: ['--disable-gpu', '--no-sandbox']
  }
},

• executors: Number of parallel processes (default: CPU count - 1).
• shardStrategy: Defines how tests are distributed.
  • 'round-robin': Distributes tests evenly across executors.
  • 'description-length': Uses test description length for distribution.
  • 'custom': Allows defining a custom strategy.
• ChromeHeadlessNoSandbox: Runs tests in headless Chrome with necessary flags.

Running Tests

To execute tests in parallel mode, run:

ng test --watch=false --browsers=ChromeHeadlessNoSandbox

Troubleshooting

• Ensure all dependencies are installed correctly.
• If tests are failing due to resource constraints, reduce the executors count in karma.conf.js.
• Use logLevel: config.LOG_DEBUG in karma.conf.js for debugging issues.