Function expectMessage

test/hotCases/worker/move-between-runtime/index.js:9–15

(w, msg)

	});

const expectMessage = (w, msg) =>
	new Promise((resolve, reject) => {
		w.onmessage = ({ data }) => {
			if (data === msg) resolve();
			else reject(new Error(data));
		};
	});

const next = w => {
	const p = expectMessage(w, "next");