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Web Test Runner
What it is
Web Test Runner is a free, open-source test runner for web applications, installed as an npm development dependency. It runs tests in parallel and isolation, placing each test file in its own browser environment. The documented headless browser launchers include Puppeteer, Playwright, Selenium, BrowserStack, and WebdriverIO. Playwright supports Chromium, Firefox, and WebKit, while BrowserStack can run tests remotely, including against older browser versions. For debugging, the runner can open a real browser window with developer tools and report browser logs, 404 responses, and errors. Its command line includes interactive watch mode, which reruns tests when files change, and code coverage with configurable thresholds and reports. Default coverage instrumentation uses Chromium. Other capabilities include ES module mocking through import maps and Mocha integration, with guidance for creating a custom test framework. The project is powered by esbuild and Rollup plugins and is MIT-licensed. The documentation points to GitHub for help and feedback, and the project invites documentation contributions.
For and against
For
- Runs test files in parallel and isolation.
- Supports Chromium, Firefox, and WebKit through Playwright.
- Includes watch mode and configurable coverage reports.
- Supports ES module mocking with import maps.
Against
- Default coverage instrumentation uses Chromium.
- Remote testing requires a documented launcher such as BrowserStack.
- Installation is as an npm development dependency.
The verdict
Web Test Runner offers browser-based execution, debugging, and coverage in an open-source package. Consider its npm setup and the default Chromium coverage instrumentation when assessing fit.
Who it suits
Web Test Runner suits developers testing web applications in browser environments. It may be useful to teams needing parallel, isolated runs, browser debugging, watch mode, or coverage reporting.
Plans and prices
Open source
MIT-licensed project · installable as an npm development dependency
Read 3 Oct 2026 · github.com
On the record
- Browser coverage
- The Playwright launcher supports bundled Chromium, Firefox, and WebKit browsers.modern-web.dev · read 3 Oct 2026
- Browser diagnostics
- It reports browser logs, 404 responses, and errors.modern-web.dev · read 3 Oct 2026
- Browser integrations
- Playwright can run tests on Chromium, Firefox, and WebKit; BrowserStack and Sauce Labs launchers are also documented.modern-web.dev · read 2 Oct 2026
- Browser launchers
- Documented launchers include Puppeteer, Playwright, Selenium, BrowserStack, and WebdriverIO.modern-web.dev · read 3 Oct 2026
- Browser testing
- It can run tests in headless browsers using Puppeteer, Playwright, Selenium, or WebdriverIO.modern-web.dev · read 2 Oct 2026
- Build tooling
- The runner is powered by esbuild and Rollup plugins.modern-web.dev · read 2 Oct 2026
- Code coverage
- Coverage supports configurable thresholds and reports, while the default coverage instrumentation uses Chromium.modern-web.dev · read 3 Oct 2026
- Debugging
- Debug mode opens a real browser window with developer tools.modern-web.dev · read 3 Oct 2026
- Execution
- Tests run in parallel and isolation, and watch mode reruns tests when files change.modern-web.dev · read 3 Oct 2026
- Installation
- The official installation instructions use npm to add @web/test-runner as a development dependency.modern-web.dev · read 3 Oct 2026
- Integrations
- The docs describe using the Playwright launcher with GitHub Actions via Microsoft's Playwright Action.modern-web.dev · read 3 Oct 2026
- License
- The project's GitHub page identifies the repository license as MIT.github.com · read 3 Oct 2026
- Maker
- Modern Web describes its goal as providing developers with guides and tools for modern web development while working closely with the browser.modern-web.dev · read 3 Oct 2026
- Maker focus
- Modern Web says its goal is to provide developers with guides and tools for building for the modern web while working closely with browser capabilities.modern-web.dev · read 2 Oct 2026
- Module mocking
- The runner can mock ES modules using import maps.modern-web.dev · read 3 Oct 2026
- Parallel and isolated tests
- Tests run in parallel and in isolation, with each test file in its own browser environment.modern-web.dev · read 2 Oct 2026
- Project status
- Modern Web says its code is open source and publicly available on GitHub, with packages published under the @web npm namespace.modern-web.dev · read 2 Oct 2026
- Purpose
- Web Test Runner is a test runner for web applications.modern-web.dev · read 3 Oct 2026
