tests: use predetermined NON_ROOT_GID

* HACKING: GID is more useful in tests than group name, so rename
input param from NON_ROOT_GROUP to NON_ROOT_GID to make it obvious
that only a group ID is now acceptable, thus allowing GID lookups
to be avoided throughout the tests.
* init.cfg (require_root_): Likewise.
* tests/misc/truncate-owned-by-other.sh: Avoid looking up the GID.
* tests/touch/now-owned-by-other.sh: Likewise.
* tests/misc/chroot-credentials.sh: Likewise.  Also fix an instance
of comparison against NON_ROOT_GROUP which would have given a false
failure if a non numeric value was passed in.
* tests/id/setgid.sh: Use previously looked up gid as a more
accurate base for the subsequent adjustment, and move
the uid lookup within chroot, rather than having the overhead
of a separate `id` invocation.

1 files changed, 1 insertions, 3 deletions

diff --git a/tests/misc/truncate-owned-by-other.sh b/tests/misc/truncate-owned-by-other.sh
index e93b7f136..e70badb6b 100755
--- a/tests/misc/truncate-owned-by-other.sh
+++ b/tests/misc/truncate-owned-by-other.sh
@@ -21,11 +21,9 @@ print_ver_ truncate
 
 require_root_
 
-group_num=$(id -g $NON_ROOT_USERNAME)
-
 # Create a file owned by root, and writable by $NON_ROOT_USERNAME.
 echo > root-owned || framework_failure_
-chgrp +$group_num . root-owned || framework_failure_
+chgrp +$NON_ROOT_GID . root-owned || framework_failure_
 chmod g+w root-owned
 
 # Ensure that the current directory is searchable by $NON_ROOT_USERNAME.