Japa vs Web Test Runner

Japa is a free testing framework for Node.js backend applications and libraries, including JSON API and browser testing. Tests can be arranged into suites and groups with lifecycle hooks, filtering, asynchronous execution, datasets, snapshots, pinned tests, and bail mode. Assertion choices include Chai-based assert, Jest-style expect, and TypeScript type assertions. Its API client tests endpoints returning JSON, XML, HTML, or plain text, while an OpenAPI plugin checks responses against a schema. Browser testing uses a Playwright-based client with browser and context management, built-in assertions, and tracing options. Coverage reporting is documented with c8 or nyc. Japa has an official VS Code extension and an AdonisJS preset. It has no separate CLI; tests run from a configured entry point with Node.js or Bun. Setup occurs inside an existing Node.js project, where users select assertion libraries and optional plugins. Japa requires Node.js 18 or later, runs without transpilers, and works only with the ES module system.

Web Test Runner is a test runner for web applications, installable as an npm development dependency. It runs tests in parallel and isolation, giving each test file its own browser environment. Headless testing is supported through launchers including Puppeteer, Playwright, Selenium, BrowserStack, and WebdriverIO. Playwright can use Chromium, Firefox, and WebKit; BrowserStack runs tests remotely, including against older browser versions. Debug mode opens a browser window with developer tools, and the runner reports browser logs, 404 responses, and errors. Its command line offers interactive watch mode that reruns tests when files change, plus code coverage with configurable thresholds and reports. Default coverage instrumentation uses Chromium. Other features include ES module mocking through import maps and Mocha integration, with guidance for a custom test framework. The project is MIT-licensed, powered by esbuild and Rollup plugins, and directs users to GitHub and Discord for help and discussion. It is free and open source.