test(browser): cover loopback CDP SSRF seam

extensions/browser/src/browser/chrome.loopback-ssrf.integration.test.ts

@@ -0,0 +1,70 @@
+import { createServer, type Server } from "node:http";
+import type { AddressInfo } from "node:net";
+import { afterEach, describe, expect, it } from "vitest";
+import { getChromeWebSocketUrl, isChromeReachable } from "./chrome.js";
+
+type RunningServer = {
+  server: Server;
+  baseUrl: string;
+};
+
+const runningServers: Server[] = [];
+
+async function startLoopbackCdpServer(): Promise<RunningServer> {
+  const server = createServer((req, res) => {
+    if (req.url !== "/json/version") {
+      res.statusCode = 404;
+      res.end("not found");
+      return;
+    }
+    const address = server.address() as AddressInfo;
+    res.setHeader("content-type", "application/json");
+    res.end(
+      JSON.stringify({
+        Browser: "Chrome/999.0.0.0",
+        webSocketDebuggerUrl: `ws://127.0.0.1:${address.port}/devtools/browser/TEST`,
+      }),
+    );
+  });
+
+  await new Promise<void>((resolve, reject) => {
+    server.once("error", reject);
+    server.listen(0, "127.0.0.1", () => resolve());
+  });
+
+  runningServers.push(server);
+  const address = server.address() as AddressInfo;
+  return {
+    server,
+    baseUrl: `http://127.0.0.1:${address.port}`,
+  };
+}
+
+afterEach(async () => {
+  await Promise.all(
+    runningServers
+      .splice(0)
+      .map(
+        (server) =>
+          new Promise<void>((resolve, reject) =>
+            server.close((err) => (err ? reject(err) : resolve())),
+          ),
+      ),
+  );
+});
+
+describe("chrome loopback SSRF integration", () => {
+  it("keeps loopback CDP HTTP reachability working under strict default SSRF policy", async () => {
+    const { baseUrl } = await startLoopbackCdpServer();
+
+    await expect(isChromeReachable(baseUrl, 500, {})).resolves.toBe(true);
+  });
+
+  it("returns the loopback websocket URL under strict default SSRF policy", async () => {
+    const { baseUrl } = await startLoopbackCdpServer();
+
+    await expect(getChromeWebSocketUrl(baseUrl, 500, {})).resolves.toMatch(
+      /\/devtools\/browser\/TEST$/,
+    );
+  });
+});