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.
testify
The essential Go toolkit for assertions, mocks, and structured test suites.
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.
tempfile
A secure, cross-platform Rust library for temporary files and directories that clean up automatically on drop.
Faker
Generate massive amounts of realistic fake data for testing, seeding, and mocking in JavaScript and TypeScript.
MSW (Mock Service Worker)
Seamless REST and GraphQL API mocking for browser and Node.js
pytest-asyncio
The pytest plugin that lets you write and run async/await test functions and fixtures directly.
Puppeteer
Node.js library for automating Chrome and Firefox over the DevTools Protocol and WebDriver BiDi
Cypress
Fast, easy, and reliable end-to-end and component testing for anything that runs in a browser.
@swc/jest
A Jest transform that compiles TypeScript and JSX with the Rust-based SWC compiler instead of Babel.
PHPUnit
The de facto standard, programmer-oriented unit testing framework for PHP.
mocha
The classic, battle-tested JavaScript test framework for Node.js and the browser, built around flexible async testing and pluggable reporters.
go-cmp
A safer, more powerful alternative to reflect.DeepEqual for comparing Go values in tests.
Chai
BDD/TDD assertion library for Node.js and the browser, framework-agnostic
identity-obj-proxy
An ES6 Proxy that echoes back every key you access, built to mock CSS Modules and other webpack style imports in Jest tests.
testcontainers-go
Programmatically spin up disposable Docker containers for Go integration and smoke tests, then tear them down automatically.
