*[Please support our friend Vadim Demedes and the people in Ukraine.](https://stand-with-ukraine.pp.ua/)*
---
# 
AVA is a test runner for Node.js with a concise API, detailed error output, embrace of new language features and thread isolation that lets you develop with confidence 🚀
Watch this repository and follow the [Discussions](https://github.com/avajs/ava/discussions) for updates.
Read our [contributing guide](.github/CONTRIBUTING.md) if you're looking to contribute (issues / PRs / etc).
Translations: [Español](https://github.com/avajs/ava-docs/blob/main/es_ES/readme.md), [Français](https://github.com/avajs/ava-docs/blob/main/fr_FR/readme.md), [Italiano](https://github.com/avajs/ava-docs/blob/main/it_IT/readme.md), [日本語](https://github.com/avajs/ava-docs/blob/main/ja_JP/readme.md), [한국어](https://github.com/avajs/ava-docs/blob/main/ko_KR/readme.md), [Português](https://github.com/avajs/ava-docs/blob/main/pt_BR/readme.md), [Русский](https://github.com/avajs/ava-docs/blob/main/ru_RU/readme.md), [简体中文](https://github.com/avajs/ava-docs/blob/main/zh_CN/readme.md)
## Why AVA?
- Minimal and fast
- Simple test syntax
- Runs tests concurrently
- Enforces writing atomic tests
- No implicit globals
- Includes TypeScript definitions
- [Magic assert](#magic-assert)
- [Isolated environment for each test file](./docs/01-writing-tests.md#test-isolation)
- [Promise support](./docs/01-writing-tests.md#promise-support)
- [Async function support](./docs/01-writing-tests.md#async-function-support)
- [Observable support](./docs/01-writing-tests.md#observable-support)
- [Enhanced assertion messages](./docs/03-assertions.md#enhanced-assertion-messages)
- [Automatic parallel test runs in CI](#parallel-runs-in-ci)
- [TAP reporter](./docs/05-command-line.md#tap-reporter)
## Usage
To install and set up AVA, run:
```console
npm init ava
```
Your `package.json` will then look like this (exact version notwithstanding):
```json
{
"name": "awesome-package",
"type": "module",
"scripts": {
"test": "ava"
},
"devDependencies": {
"ava": "^5.0.0"
}
}
```
Or if you prefer using Yarn:
```console
yarn add ava --dev
```
Alternatively you can install `ava` manually:
```console
npm install --save-dev ava
```
*Make sure to install AVA locally. AVA cannot be run globally.*
Don't forget to configure the `test` script in your `package.json` as per above.
### Create your test file
Create a file named `test.js` in the project root directory.
_Note that AVA's documentation assumes you're using ES modules._
```js
import test from 'ava';
test('foo', t => {
t.pass();
});
test('bar', async t => {
const bar = Promise.resolve('bar');
t.is(await bar, 'bar');
});
```
### Running your tests
```console
npm test
```
Or with `npx`:
```console
npx ava
```
Run with the `--watch` flag to enable AVA's [watch mode](docs/recipes/watch-mode.md):
```console
npx ava --watch
```
## Supported Node.js versions
AVA supports the latest release of any major version that [is supported by Node.js itself](https://github.com/nodejs/Release#release-schedule). Read more in our [support statement](docs/support-statement.md).
## Highlights
### Magic assert
AVA adds code excerpts and clean diffs for actual and expected values. If values in the assertion are objects or arrays, only a diff is displayed, to remove the noise and focus on the problem. The diff is syntax-highlighted too! If you are comparing strings, both single and multi line, AVA displays a different kind of output, highlighting the added or missing characters.
### Clean stack traces
AVA automatically removes unrelated lines in stack traces, allowing you to find the source of an error much faster, as seen above.
### Parallel runs in CI
AVA automatically detects whether your CI environment supports parallel builds. Each build will run a subset of all test files, while still making sure all tests get executed. See the [`ci-parallel-vars`](https://www.npmjs.com/package/ci-parallel-vars) package for a list of supported CI environments.
## Documentation
Please see the [files in the `docs` directory](./docs):
* [Writing tests](./docs/01-writing-tests.md)
* [Execution context](./docs/02-execution-context.md)
* [Assertions](./docs/03-assertions.md)
* [Snapshot testing](./docs/04-snapshot-testing.md)
* [Command line (CLI)](./docs/05-command-line.md)
* [Configuration](./docs/06-configuration.md)
* [Test timeouts](./docs/07-test-timeouts.md)
### Common pitfalls
We have a growing list of [common pitfalls](docs/08-common-pitfalls.md) you may experience while using AVA. If you encounter any issues you think are common, comment in [this issue](https://github.com/avajs/ava/issues/404).
### Recipes
- [Test setup](docs/recipes/test-setup.md)
- [TypeScript](docs/recipes/typescript.md)
- [Shared workers](docs/recipes/shared-workers.md)
- [Watch mode](docs/recipes/watch-mode.md)
- [When to use `t.plan()`](docs/recipes/when-to-use-plan.md)
- [Passing arguments to your test files](docs/recipes/passing-arguments-to-your-test-files.md)
- [Splitting tests in CI](docs/recipes/splitting-tests-ci.md)
- [Code coverage](docs/recipes/code-coverage.md)
- [Endpoint testing](docs/recipes/endpoint-testing.md)
- [Browser testing](docs/recipes/browser-testing.md)
- [Testing Vue.js components](docs/recipes/vue.md)
- [Debugging tests with Chrome DevTools](docs/recipes/debugging-with-chrome-devtools.md)
- [Debugging tests with VSCode](docs/recipes/debugging-with-vscode.md)
- [Debugging tests with WebStorm](docs/recipes/debugging-with-webstorm.md)
- [Isolated MongoDB integration tests](docs/recipes/isolated-mongodb-integration-tests.md)
- [Testing web apps using Puppeteer](docs/recipes/puppeteer.md)
- [Testing web apps using Selenium WebDriverJS](docs/recipes/testing-with-selenium-webdriverjs.md)
## FAQ
### How is the name written and pronounced?
AVA, not Ava or ava. Pronounced [`/ˈeɪvə/`](media/pronunciation.m4a?raw=true): Ay (f**a**ce, m**a**de) V (**v**ie, ha**v**e) A (comm**a**, **a**go)
### What is the header background?
It's the [Andromeda galaxy](https://simple.wikipedia.org/wiki/Andromeda_galaxy).
### What is the difference between concurrency and parallelism?
[Concurrency is not parallelism. It enables parallelism.](https://stackoverflow.com/q/1050222)
## Support
- [GitHub Discussions](https://github.com/avajs/ava/discussions)
## Related
- [eslint-plugin-ava](https://github.com/avajs/eslint-plugin-ava) — Lint rules for AVA tests
- [@ava/typescript](https://github.com/avajs/typescript) — Test TypeScript projects
- [@ava/cooperate](https://github.com/avajs/cooperate) — Low-level primitives to enable cooperation between test files
- [@ava/get-port](https://github.com/avajs/get-port) — Reserve a port while testing
## Links
- [AVA stickers, t-shirts, etc](https://www.redbubble.com/people/sindresorhus/works/30330590-ava-logo)
- [Awesome list](https://github.com/avajs/awesome-ava)
- [Do you like AVA? Donate here!](https://opencollective.com/ava)
- [More…](https://github.com/avajs/awesome-ava)
## Team
[](https://github.com/novemberborn) | [](https://github.com/sindresorhus)
---|---
[Mark Wubben](https://novemberborn.net) | [Sindre Sorhus](https://sindresorhus.com)
###### Former
- [Kevin Mårtensson](https://github.com/kevva)
- [James Talmage](https://github.com/jamestalmage)
- [Juan Soto](https://github.com/sotojuan)
- [Jeroen Engels](https://github.com/jfmengels)
- [Vadim Demedes](https://github.com/vadimdemedes)
