#!/bin/sh
# Ensure that shuf randomizes its input.

# Copyright (C) 2006, 2007 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 <http://www.gnu.org/licenses/>.

if test "$VERBOSE" = yes; then
  set -x
  shuf --version
fi

pwd=`pwd`
t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$
trap 'status=$?; cd "$pwd" && chmod -R u+rwx $t0 && rm -rf $t0 && exit $status' 0
trap '(exit $?); exit $?' 1 2 13 15

framework_failure=0
mkdir -p $tmp || framework_failure=1
cd $tmp || framework_failure=1
seq 100 > in || framework_failure=1

if test $framework_failure = 1; then
  echo "$0: failure in testing framework" 1>&2
  (exit 1); exit 1
fi

fail=0

shuf in >out || fail=1

# Fail if the input is the same as the output.
# This is a probabilistic test :-)
# However, the odds of failure are very low: 1 in 100! (~ 1 in 10^158)
cmp in out > /dev/null && { fail=1; echo "not random?" 1>&2; }

# Fail if the sorted output is not the same as the input.
sort -n out > out1
cmp in out1 || { fail=1; echo "not a permutation" 1>&2; }

# Exercise shuf's -i option.
shuf -i 1-100 > out || fail=1
cmp in out > /dev/null && { fail=1; echo "not random?" 1>&2; }
sort -n out > out1
cmp in out1 || { fail=1; echo "not a permutation" 1>&2; }

# Exercise shuf's -e option.
t=`shuf -e a b c d e | sort | fmt`
test "$t" = 'a b c d e' || { fail=1; echo "not a permutation" 1>&2; }

# Before coreutils-6.3, this would infloop.
# "seq 1860" produces 8193 (8K + 1) bytes of output.
seq 1860 | shuf > /dev/null || fail=1

(exit $fail); exit $fail