Testing

12-month change compares the average of the last 4 weeks of downloads with the first 4 weeks of the 52-week series. Gzip size is for the whole package, as measured by Bundlephobia. "-" means the value has not been fetched.

• jest-cdk-snapshotJest matcher for cdk cloudformation comparisons.
• @rstest/playwrightPlaywright fixture integration for Rstest
• @adcp/sdkAdCP SDK — client, server, and compliance harnesses for the AdContext Protocol (MCP + A2A)
• vitest-consoleQuickly mock various console methods in Vitest and track their calls with custom matchers
• react-native-test-runnerRun tests in React Native's environment.
• unexpected-messyUnexpected plugin for the messy library
• spec-xunit-fileMocha reporter which displays Spec output and generates xunit XML file
• @inquirer/testingInquirer testing utilities
• tuistoryPlaywright-like testing for TUI applications
• stylelint-test-rule-nodeA Stylelint rule tester using Node.js built-in test runner.
• mockserver-nodeNode.js module and Grunt plugin to start and stop MockServer
• vitest-mock-commonjsModule loader shims 'require' to allow mocking code-under-test CommonJS modules from vitest
• handlebars-jestHandlebars transformer for Jest
• @zendesk/laikaTest, mock, intercept and modify Apollo Client's operations — in both browser and unit tests!
• @epic-web/test-serverUtility for creating HTTP and WebSocket servers for testing
• mustTesting and assertion library with friendly BDD syntax — awesome.must.be.true(). Many expressive matchers and is test runner and framework agnostic. Follows RFC 2119 with its use of MUST. Good and well tested stuff.
• @golevelup/ts-sinonUtilities for making testing [NestJS](https://docs.nestjs.com) applications easier.
• mocha-sinonmocha integration for sinon
• @typedorm/testingTypeDORM - testing utilities
• zombieInsanely fast, full-stack, headless browser testing using Node.js
• test-data-botGenerate test data for your tests easily.
• playwright-testing-libraryplaywright + dom-testing-library
• chi-square-a-b-testingNpm module for calculating chi-square test that gives us p-value for statistical significance with practical use in A/B testing.
• @open-wc/karma-esmKarma plugin for testing with es modules
• msw-when-thenA non-invasive 'when-then' style API for MSW
• reregexpGenerate a random string match a given regular expression, suitable for mocking strings.
• earlErgonomic, modern and type-safe assertion library
• acquitParse BDD tests (Mocha, Jasmine) to generate documentation
• @quramy/jest-prisma[](https://github.com/Quramy/jest-prisma/actions) [](https://badge.fury.io/js/@quramy%2Fjest-prisma) [![Git
• babel-plugin-rewire-exportsBabel plugin for stubbing (ES6, ES2015) module exports
• mocha-loaderMocha loader for webpack
• quickpicklePlugin for Vitest to run tests written in Gherkin Syntax.
• @serenity-js/playwrightAdapter that integrates @serenity-js/web with Playwright, enabling Serenity/JS reporting and using the Screenplay Pattern to write component and end-to-end test scenarios
• @bahmutov/spokChecks a given object against a given set of specifications to keep you from writing boilerplate tests.
• image-crop-or-padA tiny, fully-tested utility to resize raw image data in node or browser, intended for visual regression testing.
• cypress-fail-on-network-errorfail cypress test on network error
• power-assert-renderersPower Assert output renderers
• karma-chai-sinonChai + Sinon-Chai + Sinon for Karma
• ecc-universalHarness-native agent operating system for Codex, OpenCode, Cursor, Gemini, Claude Code, and terminal workflows - skills, hooks, rules, MCP conventions, and operator control-plane patterns
• playwright-i18next-fixture<div align="center"> <br> <header> <img src="https://github.com/cubanducko/playwright-i18next-fixture/blob/main/assets/logo.png?raw=true" height="64" /> </header> <br> <h1>playwright-i18next-fixture</h1> <p> 📝 Use your `i18next` translati
• mocha-phantomjsRun mocha browser tests in phantomjs via the command line
• chai-almostExtends chai with assertions that allow for floating point rounding errors
• @deanwhillier/jest-matchmedia-mockMock for fully testing any media queries with Jest
• cypress-firebaseUtilities to help testing Firebase projects with Cypress.
• @computer-use/nut-jsNative system automation for node.js
• fs-teardownTeardown API for testing file system-dependent code.
• rollup-plugin-unassertRollupJS plugin to remove assertion calls via Unassert
• @web/dev-server-import-mapsPlugin for using import maps in @web/dev-server
• enzyme-adapter-react-15JavaScript Testing utilities for React
• karma-mocha-webworkerKarma plugin which runs your mocha tests in a WebWorker

• selenium-webdriver vs wd
• @appium/types vs selenium-webdriver
• msw vs json-server
• @copilotkit/aimock vs mock-socket
• @appium/types vs wd
• mockttp vs ts-mockito
• mock-socket vs ts-mockito
• rewire vs ng-mocks
• msw vs miragejs
• codeceptjs vs playwright-bdd
• codeceptjs vs nightwatch
• mocha vs jasmine-core
• mock-socket vs ng-mocks
• fast-check vs rewire
• ts-jest vs @golevelup/ts-jest