Rstest vs Web Test Runner

Rstest is a free, open-source testing framework for JavaScript and TypeScript, built on Rsbuild and Rspack. It bundles tests through Rspack’s dependency-graph build process and applies SWC transforms. Projects can reuse configuration from Rsbuild, Rslib, or Rspack, including aliases, transforms, and plugins. Tests run in Node.js, simulated DOM environments with jsdom or happy-dom, and real browsers. Browser Mode uses Playwright to run tests in Chromium, Firefox, and WebKit; an integration supports end-to-end tests against local, preview, or deployed URLs. Rstest can also load Module Federation remotes in Node, JSDOM, and Browser Mode. Its built-in tools include Jest-compatible assertions, snapshots, mocks, spies, lifecycle hooks, file-level isolation, reporters, filtering, and coverage reporting. For CI, it supports multi-project testing, sharding, blob report merging, and coverage thresholds. The Rstack VS Code extension lets users browse, run, and debug tests. The quick start requires Node.js 20.19.0 or newer, and recommends the Node.js LTS version. Rstest is released under the MIT license.

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.