For open source JS modules.
To be used in the browser, you may also want to run tests with testEnvironment: jsdom in jest.config.js.
- Runs tests on both commit pushes as well as pull request activity.
- Runs tests on LTS versions of node (currently 10 and 12) as well as the currently active versions of node (currently 13 and 14).
- Sets the maximum number of workers to 1 per CPU (2/2). You can increase this if your tests are less CPU-intensive and more concurrent (e.g. with external API calls or it has a lot of sleeps for some reason).