Rstest vs Testem

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.

Testem is a JavaScript test runner for running tests in Node.js, real desktop browsers, or a launcher you configure. It supports Jasmine, QUnit, Mocha, and custom framework adapters, and can be used for unit, integration, end-to-end-style, or custom test setups. Browser runs can use Chrome, Firefox, Safari, or Edge, including a Headless Chrome launcher. In development mode, a terminal interface watches project files and reruns tests after relevant changes; CI mode can run tests in available browsers in parallel. Testem includes CI reporters for TAP, dot, xunit, and TeamCity, with custom reporters available. Listed preprocessing support includes Babel, TypeScript, Browserify, ESLint, JSHint, JSLint, and CoffeeScript. Its API provides startDev, startCI, and startServer modes, and coverage reporting is supported. It works with GitHub Actions, Jenkins, and TeamCity. Testem is free and open source under the MIT license, and runs on Linux, macOS, and Windows. It requires a supported Node.js runtime: ^22.17.0, ^24.0.0, or >=26.0.0.