How to do A/B testing with Cloudflare workers

I'm looking for an example of what these two lines of code look like in a functioning A/B testing worker. From https://developers.cloudflare.com/workers/examples/ab-testing

const TEST_RESPONSE = new Response("Test group") // e.g. await fetch("/test/sompath", request)
const CONTROL_RESPONSE = new Response("Control group") // e.g. await fetch("/control/sompath", request)

I used the examples, subsituting the paths I’m using, and got a syntax error saying await can only be used in async. So I changed the function to async function handleRequest(request) and got a 500 error.

What should these two lines look like for the code to work?

from How to do A/B testing with Cloudflare workers