tests: avoid test failure when root's primary group-ID is not 0

* tests/cp/preserve-gid: Expect a cp-without-`-p'-created file to
have a group ID of $(id -g).  Reported by Jarod Wilson.  Details in
http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/13803/focus=13837

diff --git a/tests/cp/preserve-gid b/tests/cp/preserve-gid
index a999322..d7f86e0 100755 (executable)
--- a/tests/cp/preserve-gid
+++ b/tests/cp/preserve-gid
@@ -19,6 +19,10 @@
 . $srcdir/test-lib.sh
 require_root_
 
+# Record primary group number, usually 0.
+# This is the group ID used when cp (without -p) creates a new file.
+primary_group_num=$(id -g)
+
 create() {
   echo "$1" > "$1" || exit 1
   chown "+$2:+$3" "$1" || exit 1
@@ -34,7 +38,7 @@ t0() {
   if test "x$s" != "x$u $g"; then
     # Allow the actual group to match that of the parent directory
     # (it was set to 0 above).
-    if test "x$s" = "x$u 0"; then
+    if test "x$s" = "x$u $primary_group_num"; then
       :
     else
       echo "$0: $* $f b: $u $g != $s" 1>&2