check for preserving file permission, compression

- adresses issue #15

test/Makefile.am

@@ -1,4 +1,5 @@
 TESTS = \
+	compress-file-permissions.sh \
 	single-file-round-trip.sh \
 	xz-compatibility-c-option.sh
 

test/compress-file-permissions.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+PIXZ=../src/pixz
+
+INPUT=$(mktemp)
+trap "rm -f $INPUT $INPUT.xz" EXIT
+
+chmod 600 $INPUT
+echo foo > $INPUT
+
+$PIXZ $INPUT
+
+[[ $(stat -c "%a" $INPUT.xz) = 600 ]]