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Jest vs Vitest comparison of testing frameworks
What are the differences between Jest and Vitest?

Jest

https://jestjs.io

Vitest

https://vitest.dev
Programming language JavaScript JavaScript
Category

Unit Testing

Unit testing, integration testing, and component testing

General info

A Unit Testing framework focused on simplicity

This is a Unit test framwork especially designed for the React.JS, Babel, TypeScript, Node, React, Angular and Vue projects. It usually worked with Enzyme(Integration testing)

Vitest is a fast, modern JavaScript test runner built on Vite

It supports unit, integration, and component testing with a Jest-compatible API, built-in mocking, and TypeScript support. Designed for speed and efficiency. It seamlessly integrates with Vite projects but can also be used independently.

xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

No

Vitest does not natively follow the xUnit test structure, but it supports similar concepts. It uses a Jest-compatible API, meaning it provides test lifecycle hooks (beforeEach, afterEach, etc.) and assertions similar to xUnit-style frameworks. However, it does not strictly adhere to classical xUnit architecture, such as NUnit, JUnit, or MSTest.

Client-side
Allows testing code execution on the client, such as a web browser

Yes

You can easily test methods, properties, UI element actions and other front-end functionalities

Yes

Vitest uses JSDOM to simulate a browser environment, making it easy to test DOM-related functionality. It has Browser Mode for running component tests in the browser. Vitest can run tests in real browsers via tools like Playwright or WebdriverIO.

Server-side
Allows testing the bahovior of a server-side code

Yes

Back-end server behaviour also can be tested with Jest much in the same way as the front-end tests.

Yes

Vitest supports server-side testing, allowing you to test Node.js and server-side logic such as APIs, databases, and backend functions. It provides native support for ESM, mocks, spies, and environment configurations.

Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

Fixtures are supported, Jest has many helper functions such as: BeforeEach and afterEach If you have some work you need to do repeatedly for many tests, beforeAll and afterAll if you only need to do setup once, at the beginning of a file.

Yes

Vitest's Test Context, inspired by Playwright Fixtures, allows defining utils, states, and fixtures for use in tests. It enables sharing context between tests using the test.context object and supports tuple syntax for fixtures, allowing customization of fixture options per test.

Group fixtures
Allows defining a fixed, specific states of data for a group of tests (group-fixtures). This ensures specific environment for a given group of tests.

Yes

Jest supports group fixtures

Yes

Vitest supports group fixtures by using describe blocks with beforeAll, beforeEach, afterEach, and afterAll hooks. These hooks allow setting up a shared state for a group of tests.

Generators
Supports data generators for tests. Data generators generate input data for test. The test is then run for each input data produced in this way.

N/A

No

Licence
Licence type governing the use and redistribution of the software

MIT License

MIT License

Mocks
Mocks are objects that simulate the behavior of real objects. Using mocks allows testing some part of the code in isolation (with other parts mocked when needed)

Jest uses a custom resolver for imports in your tests making it simple to mock any object outside of your test’s scope. You can use mocked imports with the rich Mock Functions API to spy on function calls with readable test syntax.

Yes

Vitest has built-in support for mocks, allowing you to mock functions, modules, timers, and spies similar to Jest.

Grouping
Allows organizing tests in groups

Yes

You can declare as many test suites as you want. Grouping of tests together is done using a describe block

Yes

Vitest supports Grouping, allowing you to organize tests into groups using describe() blocks.

Other
Other useful information about the testing framework

Vitest provides a watch mode for instant test re-runs, ESM-first architecture for modern development, parallel and concurrent test execution for speed, custom reporters for CI/CD integration, and fake timers for testing time-dependent code.