Is this the kind of thing you're looking for? See also reset_outputs in Test::Builder.

#!/usr/bin/env perl
use warnings;
use strict;
use Test::More tests=>200;

use File::Spec;
Test::More->builder->output(File::Spec->devnull);

is 1,1 for 1..199; # lots of output

is 1,2, 'test failure';
print "print\n";
warn "warn\n";
diag "diag";
note "note";

__END__

1..200
#   Failed test 'test failure'
#   at tst.pl line 11.
#          got: '1'
#     expected: '2'
print
warn
# diag
# Looks like you failed 1 test of 200.
[download]