Example

Component

<script>
export let name
let buttonText = 'Button'
function handleClick() {
buttonText = 'Button Clicked'
}
</script>
<h1>Hello {name}!</h1>
<button on:click="{handleClick}">{buttonText}</button>

Test

// NOTE: jest-dom adds handy assertions to Jest and it is recommended, but not required.
import '@testing-library/jest-dom'
import {render, fireEvent} from '@testing-library/svelte'
import Comp from '../Comp'
test('shows proper heading when rendered', () => {
const {getByText} = render(Comp, {name: 'World'})
expect(getByText('Hello World!')).toBeInTheDocument()
})
// Note: This is as an async test as we are using `fireEvent`
test('changes button text on click', async () => {
const {getByText} = render(Comp, {name: 'World'})
const button = getByText('Button')
// Using await when firing events is unique to the svelte testing library because
// we have to wait for the next `tick` so that Svelte flushes all pending state changes.
await fireEvent.click(button)
expect(button).toHaveTextContent('Button Clicked')
})

For additional resources, patterns and best practices about testing svelte components and other svelte features take a look at the Svelte Society testing recipe.

Last updated on by Sidharth Vinod