svelte/test/runtime/samples/transition-js-dynamic-component/_config.js

export default {
	get props() {
		return { x: true };
	},

	html: `
		<div>a</div>
	`,

	test({ assert, component, target, raf }) {
		component.x = false;

		assert.htmlEqual(
			target.innerHTML,
			`
			<div>a</div>
			<div>b</div>
		`
		);

		const [a, b] = target.querySelectorAll('div');

		raf.tick(25);

		assert.equal(a.a, 0.75);
		assert.equal(b.b, 0.25);

		raf.tick(100);

		assert.equal(a.a, 0);
		assert.equal(b.b, 1);

		assert.htmlEqual(
			target.innerHTML,
			`
			<div>b</div>
		`
		);
	}
};