Intern vs Mocha

Intern is a free, open-source test system for JavaScript libraries and applications. It supports unit and functional testing, with tests written in JavaScript or TypeScript using TDD or BDD styles. Tests can run in Node.js, web browsers, or across multiple browsers and platforms through the Intern runner, with parallel execution and code coverage reporting. The project can target web pages and native or hybrid iOS and Android applications. For browser automation, it supports WebDriver-compatible tools and services, including Selenium, Appium, and Selendroid. Listed cloud options include Sauce Labs, BrowserStack, TestingBot, and a user’s own Selenium Grid. Continuous-integration integrations include Travis CI, Jenkins, and TeamCity. Intern’s extensible architecture allows custom test interfaces, executors, and reporters. It runs on Android, iOS, Linux, macOS, self-hosted environments, the web, and Windows. Installation is provided through npm, and the project uses the New BSD license.

Mocha is a free, open-source JavaScript test framework that runs in Node.js and browsers. Tests run serially by default, and uncaught exceptions are associated with their test cases. Asynchronous tests can use callbacks or returned promises, while parallel execution is available in Node.js but not in browsers. The command-line interface defaults to the BDD interface and spec reporter; browser runs default to the HTML reporter, and reporters can be configured. Installation as a development dependency is documented for npm, pnpm, and yarn. Mocha 12 requires Node.js ^20.19.0 or >=22.12.0, and browser builds document support for evergreen Chrome, Edge, Firefox, and Safari. It supports JavaScript and TypeScript, parameterized cases, and lists editor-related packages for TextMate, JetBrains IDEs, Wallaby.js, Emacs, and VS Code. Built-in mocks are not included. The project points users to Discord and documentation explainers for more information.