diff --git a/dom/src/threads/test/test_longThread.html b/dom/src/threads/test/test_longThread.html
index ace3f106b3d..df1713f33b4 100644
--- a/dom/src/threads/test/test_longThread.html
+++ b/dom/src/threads/test/test_longThread.html
@@ -25,6 +25,7 @@ Tests of DOM Worker Threads (Bug 437152)
     switch (event.data) {
       case "done":
         if (++doneThreads == numThreads) {
+          ok(true, "All messages received from workers");
           SimpleTest.finish();
         }
         break;