Testing & Mocking Packages
Testing frameworks, assertion libraries, and mocking tools for writing reliable unit, integration, and end-to-end tests (testify, pytest, Vitest).
Packages in Testing & Mocking
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Vitest
A blazing-fast unit testing framework powered by Vite, with Jest-compatible APIs out of the box.
Playwright
Cross-browser end-to-end web testing and browser automation with a single API for Chromium, Firefox, and WebKit.
jsdom
A pure-JavaScript implementation of the WHATWG DOM and HTML standards for Node.js.
React Testing Library
Simple and complete React DOM testing utilities that encourage good testing practices.
jest-dom
Custom Jest matchers for asserting on the state of the DOM in your tests.
jest
Delightful JavaScript testing with zero-config setup, snapshots, mocking, and coverage
user-event
Simulates the full sequence of real browser events so Testing Library tests behave the way an actual user does.
pytest
The Python testing framework that makes writing small tests easy and scales to complex functional test suites.
Storybook
The industry-standard workshop for building, documenting, and testing UI components in isolation, across every major frontend framework.
DOM Testing Library
Simple, framework-agnostic DOM query utilities that test your UI the way real users interact with it.
Faker
Generate massive amounts of realistic fake data for testing, seeding, and mocking in JavaScript and TypeScript.
Cypress
Fast, easy, and reliable end-to-end and component testing for anything that runs in a browser.
mocha
The classic, battle-tested JavaScript test framework for Node.js and the browser, built around flexible async testing and pluggable reporters.
Chai
BDD/TDD assertion library for Node.js and the browser, framework-agnostic
c8
Native V8 code coverage for Node.js, with Istanbul-compatible reports and zero build-step setup.
jest-junit
A Jest reporter that converts test results into JUnit-compatible XML for CI dashboards and test-analytics tools.
Ginkgo
A mature, BDD-style testing framework for Go that pairs with Gomega to write expressive, parallelizable specs.
start-server-and-test
Starts your dev server, waits for it to respond, runs your test command, then shuts the server down automatically.
deep-equal
A standalone port of Node's own assert.deepEqual algorithm, giving spec-accurate deep equality checks in Node and the browser alike.
jest-extended
Additional custom matchers for Jest to extend and simplify your test assertions.
vitest-canvas-mock
A drop-in HTML canvas mock for Vitest that emulates spec-accurate CanvasRenderingContext2D behavior in jsdom test environments.
chrome-remote-interface
A Node.js client for the Chrome DevTools Protocol, exposing every browser command, event, and type as a plain JavaScript API.
randexp.js
Generates random strings that match any given JavaScript regular expression.
uvu
An extremely fast, lightweight test runner for Node.js and the browser, with optional browser-safe assertions.
