diff --git a/addons/bus/static/tests/helpers/websocket_event_deferred.js b/addons/bus/static/tests/helpers/websocket_event_deferred.js
index 7ad5d40f5ff..0ab3b942a24 100644
--- a/addons/bus/static/tests/helpers/websocket_event_deferred.js
+++ b/addons/bus/static/tests/helpers/websocket_event_deferred.js
@@ -60,38 +60,43 @@ export function waitUntilSubscribe(...requiredChannels) {
  *
  * @returns {import("@web/core/utils/concurrency").Deferred} */
 export function waitForChannels(channels, { operation = "add" } = {}) {
-    const successDeferred = makeDeferred();
-    const failTimeout = setTimeout(() => {
-        const failMessage = `Waited ${TIMEOUT}ms for ${channels.join(", ")} to be ${
-            operation === "add" ? "added" : "deleted"
-        }`;
+    const missingChannels = new Set(channels);
+    const deferred = makeDeferred();
+    function check({ crashOnFail = false } = {}) {
+        const success = missingChannels.size === 0;
+        if (!success && !crashOnFail) {
+            return;
+        }
         unpatch();
-        QUnit.assert.ok(false, failMessage);
-        successDeferred.resolve();
-    }, TIMEOUT);
-    const channelsSeen = new Set();
+        clearTimeout(failTimeout);
+        const msg = success
+            ? `Channel(s) [${channels.join(", ")}] ${operation === "add" ? "added" : "deleted"}.`
+            : `Waited ${TIMEOUT}ms for [${channels.join(", ")}] to be ${
+                  operation === "add" ? "added" : "deleted"
+              }`;
+        QUnit.assert.ok(success, msg);
+        if (success) {
+            deferred.resolve();
+        } else {
+            deferred.reject(new Error(msg));
+        }
+    }
+    const failTimeout = setTimeout(() => check({ crashOnFail: true }), TIMEOUT);
+    registerCleanup(() => {
+        if (missingChannels.length > 0) {
+            check({ crashOnFail: true });
+        }
+    });
     const worker = patchWebsocketWorkerWithCleanup();
+    const workerMethod = operation === "add" ? "_addChannel" : "_deleteChannel";
     const unpatch = patch(worker, {
-        async [operation === "add" ? "_addChannel" : "_deleteChannel"](client, channel) {
-            await super[operation === "add" ? "_addChannel" : "_deleteChannel"](client, channel);
-            if (channels.includes(channel)) {
-                channelsSeen.add(channel);
-            }
-            if (channelsSeen.size === channels.length) {
-                unpatch();
-                QUnit.assert.ok(
-                    true,
-                    `Channel(s) ${channels.join(", ")} ${
-                        operation === "add" ? "added" : "deleted"
-                    }.`
-                );
-                successDeferred.resolve();
-                clearTimeout(failTimeout);
-            }
+        async [workerMethod](client, channel) {
+            await super[workerMethod](client, channel);
+            missingChannels.delete(channel);
+            check();
         },
     });
-    registerCleanup(unpatch);
-    return successDeferred;
+    return deferred;
 }
 
 /**