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Andrew Clark
a8875eab7f
This fixes a handful of tests that were accidentally relying on React synchronously queuing work in the Scheduler after a setState. Usually this is because they use a lower level SchedulerMock method instead of either `act` or one of the `waitFor` helpers. In some cases, the solution is to switch to those APIs. In other cases, if we're intentionally testing some lower level behavior, we might have to be a bit more clever. Co-authored-by: Tianyu Yao <skyyao@fb.com>
react-test-renderer
This package provides an experimental React renderer that can be used to render React components to pure JavaScript objects, without depending on the DOM or a native mobile environment.
Essentially, this package makes it easy to grab a snapshot of the "DOM tree" rendered by a React DOM or React Native component without using a browser or jsdom.
Documentation:
https://reactjs.org/docs/test-renderer.html
Usage:
const ReactTestRenderer = require('react-test-renderer');
const renderer = ReactTestRenderer.create(
<Link page="https://www.facebook.com/">Facebook</Link>
);
console.log(renderer.toJSON());
// { type: 'a',
// props: { href: 'https://www.facebook.com/' },
// children: [ 'Facebook' ] }
You can also use Jest's snapshot testing feature to automatically save a copy of the JSON tree to a file and check in your tests that it hasn't changed: https://jestjs.io/blog/2016/07/27/jest-14.html.