diff --git a/services/edge-broker/test/broker.test.mjs b/services/edge-broker/test/broker.test.mjs
index e3290dd3..538ad3ae 100644
--- a/services/edge-broker/test/broker.test.mjs
+++ b/services/edge-broker/test/broker.test.mjs
@@ -24,6 +24,20 @@ function waitForClose(socket) {
   });
 }
 
+async function waitFor(predicate, { timeoutMs = 1000, intervalMs = 10, description = "condition" } = {}) {
+  const deadline = Date.now() + timeoutMs;
+
+  while (Date.now() < deadline) {
+    if (predicate()) {
+      return;
+    }
+
+    await new Promise((resolve) => setTimeout(resolve, intervalMs));
+  }
+
+  throw new Error(`Timed out waiting for ${description}`);
+}
+
 test("broker dispatches commands to connected agents", async () => {
   const broker = createBrokerServer({ authMode: "stub", sharedSecret: "secret", commandTimeoutMs: 2000 });
   const address = await broker.listen(0);
@@ -165,6 +179,7 @@ test("broker closes browser shell sessions immediately when no agent is connecte
   const browser = new WebSocket(`ws://127.0.0.1:${port}/ws/browser-shell?token=session-token`);
   await new Promise((resolve) => browser.once("open", resolve));
   await waitForClose(browser);
+  await waitFor(() => closedSessions.length === 1, { description: "offline shell session close callback" });
 
   assert.deepEqual(closedSessions, [{ transcript: "", reason: "agent_offline" }]);