diff -r 8c938e9af113 -r f19b314d8475 tests/test-topic.t
--- a/tests/test-topic.t	Tue Jul 04 00:15:36 2017 +0530
+++ b/tests/test-topic.t	Tue Jul 04 01:30:14 2017 +0530
@@ -777,3 +777,28 @@
   |  date:        Thu Jan 01 00:00:00 1970 +0000
   |  summary:     start on fran
   |
+
+Testing for updating to t0
+==========================
+
+  $ hg stack
+  ### topic: changewut (2 heads)
+  ### branch: default, 5 behind
+  t3: fran?
+  t1^ start on fran (base)
+  t2@ gamma (current)
+  t1: start on fran
+  t0^ Add file delta (base)
+  $ hg up t0
+  preserving the current topic 'changewut'
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg topic
+   * changewut
+  $ hg stack
+  ### topic: changewut (2 heads)
+  ### branch: default, 5 behind
+  t3: fran?
+  t1^ start on fran (base)
+  t2: gamma
+  t1: start on fran
+  t0^ Add file delta (base)