This is perl 5, version 20, subversion 2 (v5.20.2) built for i586-linux-gnu-thread-multi-64int
(with 42 registered patches, see perl -V for more detail)

##</code><code>##

#!/usr/bin/perl

use DBI;
use strict;
use warnings;

my $dbh;

sub onevaluesql($) {
  my ($command) = @_;
  my $sth=$dbh->prepare($command);
  $sth->execute();
  my ($value) = $sth->fetchrow_array();
  $sth->finish();
  return $value;
}

sub test($$) {
  my ($testname,$test) = @_;
  $dbh->do("insert into test(name,test) values (?,?);",undef,$testname,$test);
  my $resulttest = 
    onevaluesql("select test from test where name='$testname';");
  if($test eq $resulttest) {
    print "$testname is successful on DBI readback.\n";
  } else {
    print "$testname failed on DBI readback. Got $resulttest where $test was expected.\n";
  }
  $dbh->commit();
  my $resulttest2 = `echo "select test from test where name='$testname';" | psql --html`;
  print "psql raw results: $resulttest2\n";
  if($resulttest2 =~ s/<td align="left">([^<]*)</td>/) {
    $resulttest2=$1;
  }  
  if($test eq $resulttest2) {
    print "$testname is successful on psql readback.\n";
  } else {
    print "$testname failed on psql readback. Got $resulttest where $test was expected.\n";    
  }
}

$dbh = DBI->connect("dbi:Pg:dbname=articles", "", "", {AutoCommit => 0, RaiseError => 1});
print "DBI is version $DBI::VERSION, DBD::Pg is version $DBD::Pg::VERSION\n";
print "client_encoding=" . onevaluesql("show client_encoding;") . ", server_encoding=" . onevaluesql("show server_encoding;") . "\n";
system "locale";
print "-------------------\n";
$dbh->do("drop table if exists test;");
$dbh->do("create table test ( name text, test text );");
$dbh->commit();
test('test1','ascii');
test('test2','äöüßÄÖÜ');
$dbh->disconnect();

##</code><code>##

DBI is version 1.631, DBD::Pg is version 3.4.2
client_encoding=UTF8, server_encoding=UTF8
LANG=de_DE.UTF-8
LANGUAGE=
LC_CTYPE="de_DE.UTF-8"
LC_NUMERIC="de_DE.UTF-8"
LC_TIME="de_DE.UTF-8"
LC_COLLATE="de_DE.UTF-8"
LC_MONETARY="de_DE.UTF-8"
LC_MESSAGES="de_DE.UTF-8"
LC_PAPER="de_DE.UTF-8"
LC_NAME="de_DE.UTF-8"
LC_ADDRESS="de_DE.UTF-8"
LC_TELEPHONE="de_DE.UTF-8"
LC_MEASUREMENT="de_DE.UTF-8"
LC_IDENTIFICATION="de_DE.UTF-8"
LC_ALL=
-------------------
test1 is successful on DBI readback.
psql raw results: <table border="1">
  <tr>
    <th align="center">test</th>
  </tr>
  <tr valign="top">
    <td align="left">ascii</td>
  </tr>
</table>
<p>(1 Zeile)<br />
</p>

test1 is successful on psql readback.
test2 is successful on DBI readback.
psql raw results: <table border="1">
  <tr>
    <th align="center">test</th>
  </tr>
  <tr valign="top">
    <td align="left">äöüÃÃÃÃ</td>
  </tr>
</table>
<p>(1 Zeile)<br />
</p>

test2 failed on psql readback. Got äöüßÄÖÜ where äöüßÄÖÜ was expected.