svelte/test/runtime/samples/animation-css/_config.js

export default {
	data: {
		things: [
			{ id: 1, name: 'a' },
			{ id: 2, name: 'b' },
			{ id: 3, name: 'c' },
			{ id: 4, name: 'd' },
			{ id: 5, name: 'e' }
		]
	},

	html: `
		<div>a</div>
		<div>b</div>
		<div>c</div>
		<div>d</div>
		<div>e</div>
	`,

	test(assert, component, target, window, raf) {
		let divs = document.querySelectorAll('div');
		divs.forEach(div => {
			div.getBoundingClientRect = function() {
				const index = [...this.parentNode.children].indexOf(this);
				const top = index * 30;

				return {
					left: 0,
					right: 100,
					top,
					bottom: top + 20
				}
			};
		})

		component.set({
			things: [
				{ id: 5, name: 'e' },
				{ id: 2, name: 'b' },
				{ id: 3, name: 'c' },
				{ id: 4, name: 'd' },
				{ id: 1, name: 'a' }
			]
		});

		divs = document.querySelectorAll('div');
		assert.ok(~divs[0].style.animation.indexOf('__svelte'));
		assert.equal(divs[1].style.animation, undefined);
		assert.equal(divs[2].style.animation, undefined);
		assert.equal(divs[3].style.animation, undefined);
		assert.ok(~divs[4].style.animation.indexOf('__svelte'));

		raf.tick(100);
		assert.deepEqual([
			divs[0].style.animation,
			divs[4].style.animation
		], ['', '']);
	}
};