react-test-renderer

Rendering components to JSON

This feature allows you to render a React component and generate a JSON output of the rendered component. This is useful for snapshot testing, where you can compare the current version of the component with a previously stored snapshot.

import React from 'react';
import renderer from 'react-test-renderer';
const component = renderer.create(<MyComponent />);
let tree = component.toJSON();
expect(tree).toMatchSnapshot();

Testing component output

This feature enables testing of the component's output. You can inspect the rendered component to verify that it has the expected props, state, or behavior. This is useful for ensuring that your component behaves correctly under various conditions.

import React from 'react';
import renderer from 'react-test-renderer';
const component = renderer.create(<MyComponent prop='value' />);
const instance = component.root;
expect(instance.props.prop).toBe('value');

Interacting with component instances

This feature allows you to interact with the component instances directly. You can simulate events or call methods on the component instance and then re-render. This is useful for testing the component's behavior in response to user interactions or lifecycle events.

import React from 'react';
import renderer from 'react-test-renderer';
class MyComponent extends React.Component {
  state = { clicked: false };
  handleClick = () => {
    this.setState({ clicked: true });
  };
  render() {
    return (<button onClick={this.handleClick}>Click me</button>);
  }
}
const component = renderer.create(<MyComponent />);
const button = component.root.findByType('button');
button.props.onClick();
expect(component.toJSON()).toMatchSnapshot();