fix(custom-widgets): address v2 merge review

e2e/shared/mock-api-server.ts

@@ -0,0 +1,31 @@
+import { createServer } from "node:http";
+
+import type { Server } from "node:http";
+
+export interface MockApiServer {
+  url: string;
+  close: () => Promise<void>;
+}
+
+export async function startMockApiServerAsync(responseBody: unknown): Promise<MockApiServer> {
+  const body = JSON.stringify(responseBody);
+  const server: Server = await new Promise((resolve) => {
+    const candidate = createServer((_request, response) => {
+      response.writeHead(200, { "content-type": "application/json" });
+      response.end(body);
+    });
+    candidate.listen(0, "0.0.0.0", () => resolve(candidate));
+  });
+  const address = server.address();
+  if (!address || typeof address === "string") {
+    server.close();
+    throw new Error("Failed to start mock API server");
+  }
+  return {
+    url: `http://host.docker.internal:${address.port}`,
+    close: () =>
+      new Promise((resolve, reject) => {
+        server.close((error) => (error ? reject(error) : resolve()));
+      }),
+  };
+}