svelte/test/runtime/samples/transition-js-if-block-intro/_config.js

export default {
	test({ assert, component, target, window, raf }) {
		component.visible = true;
		const div = target.querySelector('div');
		assert.equal(window.getComputedStyle(div).opacity, 0);

		raf.tick(200);
		assert.equal(window.getComputedStyle(div).opacity, 0.5);

		raf.tick(400);
		assert.equal(window.getComputedStyle(div).opacity, 1);

		raf.tick(500);
	}
};