Thanks foxcub, that did the trick. I just had to delete whitespace to pass the test :) 
use strict;
use warnings;
use HTML::Element;
use Test::More qw(no_plan);

my $literal = HTML::Element->new('~literal',
    'text' => ' '
  );

my $element = HTML::Element->new('td', "class"=>"zwischanspalte");
$element->push_content($literal);

my $expected = '<td class="zwischanspalte">&nbsp;</td>';

my $html = $element->as_HTML();
$html =~ s/[\r\n]//;
is($html, $expected);

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In reply to Re^2: How do I create non-breaking space (&nbsp; ) with HTML::Element? by tphyahoo
in thread How do I create non-breaking space (&nbsp; ) with HTML::Element? by tphyahoo

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