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

AVA

https://github.com/avajs/ava

Vitest

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

Unit Testing, Intergration Testing

Unit testing, integration testing, and component testing

General info

Futuristic, new, fast and concurrent JavaScript test runner with simple test syntax

AVA is a test runner for Node.js with a concise API, detailed error output. JS is a single-threaded but Node.JS is a parallel due to it's async behaviour. Ava leverages that and it can run tests concurrently

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

However Ava supports the TAP format which allows us to use the tap-xunit reporter to produce xUnit (JUnit) XML

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 write tests for the DOM with Ava, testing front-end components is easy with Ava

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

Ava utilizes the async I/O nature of Node and runs concurrent tests on NodeJs applications' back-endsA node server can have its endpoints tested with Ava

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

Using Ava's ava-fixture library it supports fixtures

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

Ava has support for 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)

AVA has no mocking built in, to mock functions you can use third party libraries like Sinon.js.

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

No

There is no support for grouping tests

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.