svelte/test/runtime/samples/await-function-promise/_config.js

const realPromise = Promise.resolve(42);

const promise = () => {};
promise.then = realPromise.then.bind(realPromise);
promise.catch = realPromise.catch.bind(realPromise);

export default {
	get props() {
		return { promise };
	},

	test({ assert, target }) {
		return promise.then(() => {
			assert.htmlEqual(
				target.innerHTML,
				`
				<p>42</p>
			`
			);
		});
	}
};