jest-circus
The next-gen test runner for Jest
## Overview Circus is a flux-based test runner for Jest that is fast, maintainable, and simple to extend. Circus allows you to bind to events via an optional event handler on any [custom environment](https://jestjs.io/docs/en/configuration#testenvironment-string). See the [type definitions](https://github.com/facebook/jest/blob/master/packages/jest-circus/src/types.ts) for more information on the events and state data currently available. ```js import NodeEnvironment from 'jest-environment-node'; import {Event, State} from 'jest-circus'; class MyCustomEnvironment extends NodeEnvironment { //... handleTestEvent(event: Event, state: State) { if (event.name === 'test_start') { // ... } } } ``` Mutating event or state data is currently unsupported and may cause unexpected behavior or break in a future release without warning. New events, event data, and/or state data will not be considered a breaking change and may be added in any minor release. ## Installation Install `jest-circus` using yarn: ```bash yarn add --dev jest-circus ``` Or via npm: ```bash npm install --save-dev jest-circus ``` ## Configure Configure Jest to use `jest-circus` via the [`testRunner`](https://jestjs.io/docs/en/configuration#testrunner-string) option: ```json { "testRunner": "jest-circus/runner" } ``` Or via CLI: ```bash jest --testRunner='jest-circus/runner' ```