Vitest Browser Preact

A modern testing setup demonstrating browser-based testing for Preact components using Vitest. This project showcases how to effectively test Preact components with real browser interactions, making it perfect for testing complex UI behaviors.

Requires vitest 4.0.0 or higher.

Getting Started

pnpm add vitest-browser-preact

Example

import { render } from 'vitest-browser-preact'
import { expect, test } from 'vitest'

test('renders counter', async () => {
  const screen = render(<Counter initialCount={1} />);
  await expect.element(screen.getByText('Count is 1')).toBeVisible();
  await screen.getByRole('button', { name: 'Increment' }).click();
  await expect.element(screen.getByText('Count is 2')).toBeVisible();
});

You can also fully rely on the page object, this library injects .render on the page object.

import { expect, test } from 'vitest'

test('renders counter', async () => {
  const screen = page.render(<Counter initialCount={1} />);
  await expect.element(screen.getByText('Count is 1')).toBeVisible();
  await screen.getByRole('button', { name: 'Increment' }).click();
  await expect.element(screen.getByText('Count is 2')).toBeVisible();
});

Render Options

The render function accepts an options object as its second parameter with the following properties:

interface ComponentRenderOptions {
  // Optional HTMLElement where the component will be rendered
  container?: HTMLElement;
  // Optional HTMLElement that serves as the base element (defaults to document.body)
  baseElement?: HTMLElement;
  // Optional wrapper component that can wrap the rendered component
  wrapper?: ({ children }: { children: JSX.Element }) => JSX.Element;
}

Example with options:

import { render } from 'vitest-browser-preact'

test('renders with custom container', () => {
  const screen = render(<MyComponent />, { 
    wrapper: ({ children }) => (
      <Context.Provider value={{ foo: 'bar' }}>
        {children}
      </Context.Provider>
    )
  });
});

Contributing

Feel free to open issues and pull requests. All contributions are welcome!

License

MIT