--- a/tests/test-template-keywords.t	Mon Feb 18 18:44:21 2019 -0500
+++ b/tests/test-template-keywords.t	Mon Feb 18 23:43:40 2019 -0500
@@ -76,6 +76,12 @@
   $ hg log -r 'wdir()' -T '{manifest}\n'
   2147483647:ffffffffffff
 
+However, for negrev, we refuse to output anything (as well as for null)
+
+  $ hg log -r 'wdir() + null' -T 'bla{negrev}nk\n'
+  blank
+  blank
+
 Changectx-derived keywords are disabled within {manifest} as {node} changes:
 
   $ hg log -r0 -T 'outer:{p1node} {manifest % "inner:{p1node}"}\n'