diff -r e15966216aec -r ff12a6c63c3d tests/test-help.t
--- a/tests/test-help.t	Sun Aug 16 00:24:29 2015 +0200
+++ b/tests/test-help.t	Sun Aug 16 10:19:00 2015 +0200
@@ -1202,6 +1202,11 @@
       ":tagmerge"
         Uses the internal tag merge algorithm (experimental).
   
+      ":union"
+        Uses the internal non-interactive simple merge algorithm for merging
+        files. It will use both left and right sides for conflict regions. No
+        markers are inserted.
+  
       Internal tools are always available and do not require a GUI but will by
       default not handle symlinks or binary files.