use warnings;
use strict;
use XML::Twig;
use XML::XPath;  # for findnodes

my $filename = 'foo.xml';
XML::Twig->new(
	twig_print_outside_roots => 1,
	keep_spaces => 1,
	twig_roots => {
		'/TestCode/TestCategory/Test' => sub {
			my ($t, $elt) = @_;
			if ( $elt->{att}{name} =~ /^CheckType_/ ) {
				my @values = $elt->findnodes('./context/value');
				# could theoretically also use XPath for the following
				if ( grep { $_->text =~ /XYZ/ } @values )
					{ $t->flush }
				else { $t->purge }
			}
			else { $t->purge }
		},
	},
)->parsefile($filename);