--- a/tests/test-command-template.t	Wed Apr 05 21:57:05 2017 +0900
+++ b/tests/test-command-template.t	Sat Apr 15 10:51:17 2017 +0900
@@ -3894,6 +3894,11 @@
   o  foo line 1
      foo line 2
 
+  $ hg log -R a -r0 -T '{desc|splitlines}\n'
+  line 1 line 2
+  $ hg log -R a -r0 -T '{join(desc|splitlines, "|")}\n'
+  line 1|line 2
+
 Test startswith
   $ hg log -Gv -R a --template "{startswith(desc)}"
   hg: parse error: startswith expects two arguments