lutece/rut

⚛️ React testing made easy. Supports DOM, Native, and custom renderers.

Rut

Rut is a DOM-less React testing library that aims to be lightweight, encourage great testing practices, and reduce flakiness and code smells. It is a wrapper and abstraction around react-test-renderer that simplifies the test writing process, while doing all the hard work behind the scenes.

import { render } from 'rut-dom';
import Input, { InputProps } from '../src/Input';

describe('<Input />', () => {
  it('renders an input field', () => {
    const { root, update } = render<InputProps>(<Input name="rut" value="foo" />);

    expect(root).toHaveProp('name', 'rut');
    expect(root).toHaveValue('foo');
    expect(root).not.toBeDisabled();

    update({ disabled: true });

    expect(root).toBeDisabled();
  });
});

The rut package provides core functionality for adapters to expand upon. For example, a DOM adapter for react-dom, a mobile native adapter for react-native, or even a custom adapter unique to your application.

Features

• Type safe by design. Test with confidence.
• First-class async support. Wait for async calls to finish before returning a rendered result. (Experimental)
• Deep act() integration. Let Rut do the heavy lifting.
• Update a component with new props, children, or a completely new element.
• Unmount a component to verify cleanup and destructor based logic.
• Dispatch DOM level events with a mocked synthetic event (and propagation coming soon!).
• Wrap all renders with a defined wrapping component and or React.StrictMode.
• Apply pre-built mocks for robust and accurate testing.
• Utilize an array of pre-built matchers for easily querying, expecting, and asserting.

Best Practices

Encourages the Arrange-Act-Assert testing pattern.

Arrange: Renders the entire component tree (instead of shallow) for a more accurate representation of your component. Requires fetches, events, contexts, and more, to be properly mocked or setup before hand.

Act: With no direct access to state or internals, it forces you to interact with your tree in the same manner your user would. Dispatch events to toggle states or execute handlers, like a form submission.

Assert: Test your expectations using pre-built matchers for common testing scenarios and patterns while avoiding implementation details.

Requirements

• React 16.9+
• Jest or another testing framework

Documentation

https://milesj.gitbook.io/rut