--- a/tests/test-drawdag.t	Mon Jul 17 15:54:15 2017 -0700
+++ b/tests/test-drawdag.t	Fri Jul 14 22:32:58 2017 -0700
@@ -117,6 +117,18 @@
    /
   o  a
   
+  $ hg manifest -r a
+  a
+  $ hg manifest -r b
+  a
+  b
+  $ hg manifest -r bar
+  a
+  b
+  $ hg manifest -r foo
+  a
+  b
+  baz
 
 Edges existed in repo are no-ops