52b694eaae
Adds a new docs website, built with Gatsby JS, to replace the old Jekyll site. Source code for the new site lives in /www (although markdown and YML data still comes from the legacy /docs folder). Changes to either markdown or website source code can be previewed on Netlify. The react-js bot should automatically add comments to each PR with preview links. (This preview is generated by running the newly-added yarn build:docs command in the root package.json.) The majority of the changes in this PR are contained within the new /www directory. However some minor modifications have been made to existing content in the /docs directory: * Modified frontmatter author block to always be an array * Small markdown formatting tweaks
2.1 KiB
id, title, permalink, layout, category
| id | title | permalink | layout | category |
|---|---|---|---|---|
| shallow-renderer | Shallow Renderer | docs/shallow-renderer.html | docs | Reference |
Importing
import ShallowRenderer from 'react-test-renderer/shallow'; // ES6
var ShallowRenderer = require('react-test-renderer/shallow'); // ES5 with npm
Overview
When writing unit tests for React, shallow rendering can be helpful. Shallow rendering lets you render a component "one level deep" and assert facts about what its render method returns, without worrying about the behavior of child components, which are not instantiated or rendered. This does not require a DOM.
For example, if you have the following component:
function MyComponent() {
return (
<div>
<span className="heading">Title</span>
<Subcomponent foo="bar" />
</div>
);
}
Then you can assert:
import ShallowRenderer from 'react-test-renderer/shallow';
// in your test:
const renderer = new ShallowRenderer();
renderer.render(<MyComponent />);
const result = renderer.getRenderOutput();
expect(result.type).toBe('div');
expect(result.props.children).toEqual([
<span className="heading">Title</span>,
<Subcomponent foo="bar" />
]);
Shallow testing currently has some limitations, namely not supporting refs.
Note:
We also recommend checking out Enzyme's Shallow Rendering API. It provides a nicer higher-level API over the same functionality.
Reference
shallowRenderer.render()
You can think of the shallowRenderer as a "place" to render the component you're testing, and from which you can extract the component's output.
shallowRenderer.render() is similar to ReactDOM.render() but it doesn't require DOM and only renders a single level deep. This means you can test components isolated from how their children are implemented.
shallowRenderer.getRenderOutput()
After shallowRenderer.render() has been called, you can use shallowRenderer.getRenderOutput() to get the shallowly rendered output.
You can then begin to assert facts about the output.