rm -f foo bar
echo -e "\ty" | expand -t 3 ../../busybox > foo
echo -e "\ty" | busybox unexpand -t 3 ../../busybox > bar
set +e
test ! -f foo -a -f bar
if [ $? = 0 ] ; then
	set -e
	diff -q foo bar
fi
rm -f foo bar
echo -e "\ty\tx" | expand -it 3 ../../busybox > foo
echo -e "\ty\tx" | busybox unexpand -it 3 ../../busybox > bar
set +e
test ! -f foo -a -f bar
if [ $? = 0 ] ; then
	set -e
	diff -q foo bar
fi