const requestURL = "https://test1.example.com"; function getResult(aBrowser) { return SpecialPowers.spawn(aBrowser, [requestURL], async function (url) { let cache = await content.caches.open("TEST_CACHE"); let response = await cache.match(url); if (response) { return response.statusText; } let result = Math.random().toString(); response = new content.Response("", { statusText: result }); await cache.put(url, response); return result; }); } IsolationTestTools.runTests( "https://test2.example.com", getResult, null, null, false, /* aUseHttps */ true );