tests: mv: add checks for cross device handling of special files

* tests/mv/mv-special-2.sh: Add test to ensure we preserve
sparse files, character devices, symlinks, when moving across
file system boundaries.
Addresses https://github.com/coreutils/coreutils/issues/136

tests/local.mk

@@ -135,6 +135,7 @@ all_root_tests =				\
   tests/mkdir/smack-root.sh			\
   tests/mv/hardlink-case.sh			\
   tests/mv/sticky-to-xpart.sh			\
+  tests/mv/mv-special-2.sh			\
   tests/rm/fail-2eperm.sh			\
   tests/rm/no-give-up.sh			\
   tests/rm/one-file-system.sh			\

tests/mv/mv-special-2.sh

@@ -0,0 +1,62 @@
+#!/bin/sh
+# Ensure that mv works with non standard copies across file systems
+
+# Copyright (C) 2025 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ mv
+
+require_root_
+
+cwd=$(pwd)
+cleanup_() { cd /; umount "$cwd/xdev"; }
+
+skip=0
+
+# Mount an ext2 loopback file system at $WHERE
+make_fs() {
+  where="$1"
+
+  mkdir "$where"  || framework_failure_
+
+  fs="$where.bin"
+  dd if=/dev/zero of="$fs" bs=8192 count=200 > /dev/null 2>&1 || skip=1
+  mkfs -t ext2 -F "$fs" || skip_ "failed to create ext2 file system"
+  mount -oloop "$fs" "$where" || skip=1
+
+  echo test > "$where"/f && test -s "$where"/f || skip=1
+
+  test $skip = 1 && skip_ 'insufficient mount/ext2 support'
+}
+
+make_fs xdev
+
+truncate -s 8G huge || framework_failure_
+mv --verbose huge xdev &&
+returns_ 1 test -e huge &&
+test -s xdev/huge || fail=1
+
+mknod devzero c 1 5 || framework_failure_
+mv --verbose devzero xdev &&
+returns_ 1 test -c devzero &&
+test -c xdev/devzero || fail=1
+
+ln -nsf blah blah   || framework_failure_
+mv --verbose blah xdev &&
+returns_ 1 test -L blah &&
+test -L xdev/blah || fail=1
+
+Exit $fail