svelte/test/runtime/samples/event-handler-dynamic/_config.js

export default {
	html: `
	<p>
		<button>set handler 1</button>
		<button>set handler 2</button>
	</p>
	<p>0</p>
	<button>click</button>
	`,

	async test({ assert, component, target, window }) {
		const [updateButton1, updateButton2, button] = target.querySelectorAll(
			'button'
		);

		const event = new window.MouseEvent('click');
		let err = "";
		window.addEventListener('error', (e) => {
			e.preventDefault();
			err = e.message;
		});

		await button.dispatchEvent(event);
		assert.equal(err, "", err);
		assert.htmlEqual(target.innerHTML, `
			<p>
				<button>set handler 1</button>
				<button>set handler 2</button>
			</p>
			<p>0</p>
			<button>click</button>
		`);

		await updateButton1.dispatchEvent(event);
		await button.dispatchEvent(event);
		assert.htmlEqual(target.innerHTML, `
			<p>
				<button>set handler 1</button>
				<button>set handler 2</button>
			</p>
			<p>1</p>
			<button>click</button>
		`);

		await updateButton2.dispatchEvent(event);
		await button.dispatchEvent(event);
		assert.htmlEqual(target.innerHTML, `
			<p>
				<button>set handler 1</button>
				<button>set handler 2</button>
			</p>
			<p>2</p>
			<button>click</button>
		`);
	},
};