guix system: search: Display default Shepherd service names.

Fixes <https://bugs.gnu.org/29707>.
Reported by Clément Lassieur <clement@lassieur.org>.

* guix/scripts/system/search.scm (service-type-default-shepherd-services)
(service-type-shepherd-names): New procedures.
(service-type->recutils): Use it.
* tests/guix-system.sh: Add test.

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/guix-system.sh b/tests/guix-system.sh
index 211c26f43db..ff9114ab744 100644
--- a/tests/guix-system.sh
+++ b/tests/guix-system.sh
@@ -1,5 +1,5 @@
 # GNU Guix --- Functional package management for GNU
-# Copyright © 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
+# Copyright © 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
 # Copyright © 2017 Tobias Geerinckx-Rice <me@tobias.gr>
 # Copyright © 2018 Chris Marusich <cmmarusich@gmail.com>
 #
@@ -267,6 +267,7 @@ guix system build "$tmpdir/config.scm" -n
 
 # Searching.
 guix system search tor | grep "^name: tor"
+guix system search tor | grep "^shepherdnames: tor"
 guix system search anonym network | grep "^name: tor"
 
 # Below, use -n (--dry-run) for the tests because if we actually tried to