add test

Author: Conduitry

packages/kit/test/apps/basics/src/hooks.server.js

@@ -56,6 +56,12 @@ export const handle = sequence(
 		}
 		return resolve(event);
 	},
+	({ event, resolve }) => {
+		if (!(event.request.headers.has('user-agent') ^ event.isSyntheticRequest)) {
+			throw new Error('Synthetic requests should have isSyntheticRequest set to true');
+		}
+		return resolve(event);
+	},
 	({ event, resolve }) => {
 		if (event.url.pathname.includes('fetch-credentialed')) {
 			// Only get the cookie at the test where we know it's set to avoid polluting our logs with (correct) warnings