diff --git a/extensions/voice-call/src/media-stream.test.ts b/extensions/voice-call/src/media-stream.test.ts
index 1874bec83f5..03c9540af9e 100644
--- a/extensions/voice-call/src/media-stream.test.ts
+++ b/extensions/voice-call/src/media-stream.test.ts
@@ -1,5 +1,3 @@
-import { once } from "node:events";
-import http from "node:http";
 import type {
   RealtimeTranscriptionProviderPlugin,
   RealtimeTranscriptionSession,
@@ -7,6 +5,12 @@ import type {
 import { describe, expect, it, vi } from "vitest";
 import { WebSocket } from "ws";
 import { MediaStreamHandler, sanitizeLogText } from "./media-stream.js";
+import {
+  connectWs,
+  startUpgradeWsServer,
+  waitForClose,
+  withTimeout,
+} from "./websocket-test-support.js";
 
 const createStubSession = (): RealtimeTranscriptionSession => ({
   connect: async () => {},
@@ -36,69 +40,18 @@ const waitForAbort = (signal: AbortSignal): Promise<void> =>
     signal.addEventListener("abort", () => resolve(), { once: true });
   });
 
-const withTimeout = async <T>(promise: Promise<T>, timeoutMs = 2000): Promise<T> => {
-  let timer: ReturnType<typeof setTimeout> | null = null;
-  const timeout = new Promise<never>((_, reject) => {
-    timer = setTimeout(() => reject(new Error(`Timed out after ${timeoutMs}ms`)), timeoutMs);
-  });
-
-  try {
-    return await Promise.race([promise, timeout]);
-  } finally {
-    if (timer) {
-      clearTimeout(timer);
-    }
-  }
-};
-
 const startWsServer = async (
   handler: MediaStreamHandler,
 ): Promise<{
   url: string;
   close: () => Promise<void>;
-}> => {
-  const server = http.createServer();
-  server.on("upgrade", (request, socket, head) => {
-    handler.handleUpgrade(request, socket, head);
-  });
-
-  await new Promise<void>((resolve) => {
-    server.listen(0, "127.0.0.1", resolve);
-  });
-
-  const address = server.address();
-  if (!address || typeof address === "string") {
-    throw new Error("Failed to resolve test server address");
-  }
-
-  return {
-    url: `ws://127.0.0.1:${address.port}/voice/stream`,
-    close: async () => {
-      await new Promise<void>((resolve, reject) => {
-        server.close((err) => (err ? reject(err) : resolve()));
-      });
+}> =>
+  startUpgradeWsServer({
+    urlPath: "/voice/stream",
+    onUpgrade: (request, socket, head) => {
+      handler.handleUpgrade(request, socket, head);
     },
-  };
-};
-
-const connectWs = async (url: string): Promise<WebSocket> => {
-  const ws = new WebSocket(url);
-  await withTimeout(once(ws, "open") as Promise<[unknown]>);
-  return ws;
-};
-
-const waitForClose = async (
-  ws: WebSocket,
-): Promise<{
-  code: number;
-  reason: string;
-}> => {
-  const [code, reason] = (await withTimeout(once(ws, "close") as Promise<[number, Buffer]>)) ?? [];
-  return {
-    code,
-    reason: Buffer.isBuffer(reason) ? reason.toString() : String(reason || ""),
-  };
-};
+  });
 
 describe("MediaStreamHandler TTS queue", () => {
   it("serializes TTS playback and resolves in order", async () => {
diff --git a/extensions/voice-call/src/webhook/realtime-handler.test.ts b/extensions/voice-call/src/webhook/realtime-handler.test.ts
index 36662b678fd..7593992843c 100644
--- a/extensions/voice-call/src/webhook/realtime-handler.test.ts
+++ b/extensions/voice-call/src/webhook/realtime-handler.test.ts
@@ -1,4 +1,3 @@
-import { once } from "node:events";
 import http from "node:http";
 import type {
   RealtimeVoiceBridge,
@@ -9,6 +8,7 @@ import { WebSocket } from "ws";
 import type { VoiceCallRealtimeConfig } from "../config.js";
 import type { CallManager } from "../manager.js";
 import type { VoiceCallProvider } from "../providers/base.js";
+import { connectWs, startUpgradeWsServer, waitForClose } from "../websocket-test-support.js";
 import { RealtimeCallHandler } from "./realtime-handler.js";
 
 function makeRequest(url: string, host = "gateway.ts.net"): http.IncomingMessage {
@@ -83,21 +83,6 @@ function makeHandler(
   );
 }
 
-const withTimeout = async <T>(promise: Promise<T>, timeoutMs = 2000): Promise<T> => {
-  let timer: ReturnType<typeof setTimeout> | null = null;
-  const timeout = new Promise<never>((_, reject) => {
-    timer = setTimeout(() => reject(new Error(`Timed out after ${timeoutMs}ms`)), timeoutMs);
-  });
-
-  try {
-    return await Promise.race([promise, timeout]);
-  } finally {
-    if (timer) {
-      clearTimeout(timer);
-    }
-  }
-};
-
 const startRealtimeServer = async (
   handler: RealtimeCallHandler,
 ): Promise<{
@@ -110,47 +95,12 @@ const startRealtimeServer = async (
     throw new Error("Failed to extract realtime stream path");
   }
 
-  const server = http.createServer();
-  server.on("upgrade", (request, socket, head) => {
-    handler.handleWebSocketUpgrade(request, socket, head);
-  });
-
-  await new Promise<void>((resolve) => {
-    server.listen(0, "127.0.0.1", resolve);
-  });
-
-  const address = server.address();
-  if (!address || typeof address === "string") {
-    throw new Error("Failed to resolve test server address");
-  }
-
-  return {
-    url: `ws://127.0.0.1:${address.port}${match[1]}`,
-    close: async () => {
-      await new Promise<void>((resolve, reject) => {
-        server.close((err) => (err ? reject(err) : resolve()));
-      });
+  return await startUpgradeWsServer({
+    urlPath: match[1],
+    onUpgrade: (request, socket, head) => {
+      handler.handleWebSocketUpgrade(request, socket, head);
     },
-  };
-};
-
-const connectWs = async (url: string): Promise<WebSocket> => {
-  const ws = new WebSocket(url);
-  await withTimeout(once(ws, "open") as Promise<[unknown]>);
-  return ws;
-};
-
-const waitForClose = async (
-  ws: WebSocket,
-): Promise<{
-  code: number;
-  reason: string;
-}> => {
-  const [code, reason] = (await withTimeout(once(ws, "close") as Promise<[number, Buffer]>)) ?? [];
-  return {
-    code,
-    reason: Buffer.isBuffer(reason) ? reason.toString("utf8") : String(reason || ""),
-  };
+  });
 };
 
 describe("RealtimeCallHandler path routing", () => {
diff --git a/extensions/voice-call/src/websocket-test-support.ts b/extensions/voice-call/src/websocket-test-support.ts
new file mode 100644
index 00000000000..dd28d13a74a
--- /dev/null
+++ b/extensions/voice-call/src/websocket-test-support.ts
@@ -0,0 +1,72 @@
+import { once } from "node:events";
+import http from "node:http";
+import { WebSocket } from "ws";
+
+export const withTimeout = async <T>(promise: Promise<T>, timeoutMs = 2000): Promise<T> => {
+  let timer: ReturnType<typeof setTimeout> | null = null;
+  const timeout = new Promise<never>((_, reject) => {
+    timer = setTimeout(() => reject(new Error(`Timed out after ${timeoutMs}ms`)), timeoutMs);
+  });
+
+  try {
+    return await Promise.race([promise, timeout]);
+  } finally {
+    if (timer) {
+      clearTimeout(timer);
+    }
+  }
+};
+
+export const startUpgradeWsServer = async (params: {
+  urlPath: string;
+  onUpgrade: (
+    request: http.IncomingMessage,
+    socket: Parameters<http.Server["emit"]>[2],
+    head: Buffer,
+  ) => void;
+}): Promise<{
+  url: string;
+  close: () => Promise<void>;
+}> => {
+  const server = http.createServer();
+  server.on("upgrade", (request, socket, head) => {
+    params.onUpgrade(request, socket, head);
+  });
+
+  await new Promise<void>((resolve) => {
+    server.listen(0, "127.0.0.1", resolve);
+  });
+
+  const address = server.address();
+  if (!address || typeof address === "string") {
+    throw new Error("Failed to resolve test server address");
+  }
+
+  return {
+    url: `ws://127.0.0.1:${address.port}${params.urlPath}`,
+    close: async () => {
+      await new Promise<void>((resolve, reject) => {
+        server.close((err) => (err ? reject(err) : resolve()));
+      });
+    },
+  };
+};
+
+export const connectWs = async (url: string): Promise<WebSocket> => {
+  const ws = new WebSocket(url);
+  await withTimeout(once(ws, "open") as Promise<[unknown]>);
+  return ws;
+};
+
+export const waitForClose = async (
+  ws: WebSocket,
+): Promise<{
+  code: number;
+  reason: string;
+}> => {
+  const [code, reason] = (await withTimeout(once(ws, "close") as Promise<[number, Buffer]>)) ?? [];
+  return {
+    code,
+    reason: Buffer.isBuffer(reason) ? reason.toString("utf8") : String(reason || ""),
+  };
+};