diff --git a/testing/web-platform/tests/mediacapture-insertable-streams/VideoTrackGenerator-with-window-tracks.https.html b/testing/web-platform/tests/mediacapture-insertable-streams/VideoTrackGenerator-with-window-tracks.https.html
index 4fe8c20c460c..da5eec21e991 100644
--- a/testing/web-platform/tests/mediacapture-insertable-streams/VideoTrackGenerator-with-window-tracks.https.html
+++ b/testing/web-platform/tests/mediacapture-insertable-streams/VideoTrackGenerator-with-window-tracks.https.html
@@ -573,29 +573,50 @@
 url
 )
 ;
+try
+{
 await
 new
 Promise
 (
+(
 resolve
+reject
+)
 =
 >
+{
 worker
 .
 onmessage
 =
+resolve
+;
+worker
+.
+onerror
+=
 (
+err
 )
 =
 >
-{
-resolve
+reject
 (
+err
+.
+message
 )
 ;
 }
 )
 ;
+return
+worker
+;
+}
+finally
+{
 URL
 .
 revokeObjectURL
@@ -603,9 +624,7 @@
 url
 )
 ;
-return
-worker
-;
+}
 }
 promise_test
 (