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.

• @test-effective/fakesTest Effective Fakes
• unexpected-mapAdd support to Unexpected for testing Map instances
• coffee-coverageIstanbul and JSCoverage-style instrumentation for CoffeeScript files.
• p-oneTest whether some promise passes a testing function
• jest-test-matrixA small utility for Jest to test all combinations of parameters for a function at once.
• @stdlib/ndarray-base-assert-is-complex-floating-point-data-typeTest if an input value is a supported ndarray complex-valued floating-point data type.
• mocker-data-generatorA simplified way to generate mock data, builds using a simple schema and with the FakerJs
• unexpected-eventemitterEventEmitter assertions for Unexpected
• zoroasterThe 2020 Most Modern Testing Framework For Node.JS With Test Contexts (Reusable BeforeEach / AfterEach Via Separate Files); Masks (Inputs/Outputs In Non-Js Files) And Fork Testing; Interactive Snapshots.
• @newmo/graphql-fake-coreGraphQL fake core library
• @newmo/graphql-codegen-fake-server-clientGraphQL Codegen plugin for generating a fake server client
• @newmo/eslint-plugin-graphql-fakeESLint plugin for GraphQL fake
• @newmo/graphql-fake-serverGraphQL fake server for testing
• @supa-media/testingReusable test suites that catch common Expo/React Native gotchas — routing conflicts, web bundle safety, React resolution, native import gating
• socket-vcr-testRecord your test suite's HTTP interactions and replay them during future test runs for fast, deterministic, accurate tests.
• dynoxideA DynamoDB emulator for testing and CI. A single static binary that starts in milliseconds, verified against real AWS.
• jest-handlebarsA Jest processor that compiles included handlebars templates
• qwenproxy-cliHigh-performance OpenAI & Anthropic compatible API gateway for Qwen with multi-account rotation, interactive TUI, and resilient tool calling.
• @augment-vir/testA universal testing suite that works with Mocha style test runners _and_ Node.js's built-in test runner.
• @stdlib/ndarray-base-assert-is-real-data-typeTest if an input value is a supported ndarray real-valued data type.
• objectmodelStrong Dynamically Typed Object Modeling for JavaScript
• zurvanA library for simulating time in Node.js
• jest-plugin-fsJest plugin for mocking out the filesystem.
• testdouble-chaiAssertion sugar for testdouble.js's verify() function
• chronokinesisModule for testing time-dependent code
• microsoft-onedrive-mockMock-Server that simulates being Microsoft OneDrive. Used for testing.
• targaryenTest Firebase security rules without connecting to Firebase.
• cypress-timeRecord timings in Cypress
• dotenv-flow-webpackA webpack plugin that allows you to securely use environment variables within your javascript web application, loading them using dotenv-flow's `.env*` files loading strategy.
• ivyaFork of Playwright's locator resolution
• vitest-mmsmongodb-memory-server integration for vitest
• @sadams/wait-for-expectWait for expectation to be true, useful for integration and end to end testing
• @serenity-js/protractorAdapter that integrates @serenity-js/web with Protractor, enabling Serenity/JS reporting and using the Screenplay Pattern to write end-to-end test scenarios
• redux-logic-testredux-logic test utilities to facilitate the testing of logic. Create mock store
• cypress-maildevAn easy-to-use cypress bunch of commands to use Maildev API for tests messages reception !
• fetch-vcrStop mocking HTTP Requests. Just record and then play them back
• @avocadostudio-ai/migration-sdkUtilities for migrating existing site content into the Avocado Studio PageDoc/BlockInstance shape
• appveyor-mochaLogging mocha test results to AppVeyor
• @apps-in-toss/devtoolsBrowser development tools for Apps in Toss mini-apps — mock SDK, floating devtools panel, and universal bundler plugin. devDependency only; contributes nothing to a production bundle
• @stdlib/number-float32-base-assert-is-same-valueTest if two single-precision floating-point numbers are the same value.
• @stdlib/assert-is-matrix-likeTest if a value is a 2-dimensional ndarray-like object.
• joi-assertAssert values using Joi schemas
• @vitest-agent/pluginVitest plugin for the vitest-agent ecosystem: owns persistence, classification, baselines, trends, and dispatches rendering to a configurable reporter.
• @stdlib/assert-is-vector-likeTest if a value is a 1-dimensional ndarray-like object.
• @scaleleap/jest-pollyIntegrate Jest with PollyJS for a smooth experience of HTTP recording.
• winston-spyTest winston logging with spies
• @marionebl/isType check values: `is.string('🦄') //=> true`
• @csvtuda/cypress-xray-pluginA Cypress plugin for uploading test results to Xray (test management for Jira)
• scenescoutSceneScout — exploratory UI testing for AI coding agents. An MCP server that gives any agent (Claude Code, Cursor, VS Code Copilot, Codex, Gemini CLI and others) a structured view of a running web app, always-on oracles, a network-level write policy, memo
• opfs-mockMock all origin private file system APIs for your Jest or Vitest tests

• 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