svetle-jest-playground/tests/test.app.js

import App from '../src/App.svelte'
import { render, cleanup } from '@testing-library/svelte'
beforeEach(cleanup)
describe('App', () => {
  test('should render greeting', () => {
    const { getByText } = render(App, { props: {} })
    expect(getByText('Hello world!'))
  })

})