Ports privsep does not allow to write into t directory.

Index: t/bigfile.t
--- t/bigfile.t.orig
+++ t/bigfile.t
@@ -1,25 +1,25 @@
 #!perl -w
 
-BEGIN
-{
-	chdir 't' if -d 't';
-}
-
 use strict;
+use File::Temp qw(tempfile);
 use Test::More tests => 2;
 
 use_ok( 'Crypt::CipherSaber' );
 
+my ($fh, $filename) = tempfile(UNLINK => 1,
+    TEMPLATE => "/tmp/smiles.png.XXXXXXXXXX");
+chdir 't' or die "Couldn't chdir: $!";
+
 my $cs = Crypt::CipherSaber->new( 'sdrawkcabsihtdaeR' );
 open( INPUT, 'smiles.cs1' ) or die "Couldn't open: $!";
 binmode(INPUT);
-open(OUTPUT, '> smiles.png') or die "Couldn't open: $!";
+open(OUTPUT, '>&', $fh) or die "Couldn't open: $!";
 binmode(OUTPUT);
 $cs->fh_crypt(\*INPUT, \*OUTPUT);
 close INPUT;
 close OUTPUT;
 
-open(TEST, 'smiles.png') or die "Couldn't open: $!";
+open(TEST, $filename) or die "Couldn't open: $!";
 my $line = <TEST>;
 
 like( $line, qr/PNG/, 'Encrypting a large file should not mangle it' );