--- a/tests/test-topic.t	Mon Sep 25 03:29:45 2017 +0530
+++ b/tests/test-topic.t	Mon Sep 25 03:30:56 2017 +0530
@@ -999,4 +999,7 @@
      topic1990 (1990-01-01 by foo)
    * topic1970 (1970-01-01 by test)
 
+  $ hg topics --age random
+  abort: cannot use --age while setting a topic
+  [255]
   $ cd ..