Allow overriding WebSocket implementation and add flaky version for testing

frontend/test-client/src/utils/flaky-fetch.ts

@@ -0,0 +1,20 @@
+import { sleep } from "./sleep";
+
+export const flakyFetchFactory =
+	(jitterScaleInSeconds: number) =>
+	async (
+		input: string | URL | globalThis.Request,
+		init?: RequestInit
+	): Promise<Response> => {
+		if (jitterScaleInSeconds > 0) {
+			await sleep(Math.random() * jitterScaleInSeconds * 1000);
+		}
+
+		const response = await fetch(input, init);
+
+		if (jitterScaleInSeconds > 0) {
+			await sleep(Math.random() * jitterScaleInSeconds * 1000);
+		}
+
+		return response;
+	};