svelte/test/runtime/samples/each-block-keyed-dynamic/_config.js

export default {
	data: {
		todos: [
			{ id: 123, description: 'buy milk' },
			{ id: 234, description: 'drink milk' }
		]
	},

	html: `
		<p>buy milk</p>
		<p>drink milk</p>
	`,

	test ( assert, component, target ) {
		const [ p1, p2 ] = target.querySelectorAll( 'p' );

		component.set({
			todos: [
				{ id: 123, description: 'buy beer' },
				{ id: 234, description: 'drink beer' }
			]
		});
		assert.htmlEqual( target.innerHTML, `
			<p>buy beer</p>
			<p>drink beer</p>
		` );

		const [ p3, p4 ] = target.querySelectorAll( 'p' );

		assert.equal( p1, p3 );
		assert.equal( p2, p4 );

		component.destroy();
	}
};