Plugin you can preload to hide diagnostics messages

NoDiag.pm

package Test2::Plugin::NoDiag;
use strict;
use warnings;

use Test2::API qw/test2_stack test2_add_callback_post_load/;

test2_add_callback_post_load(sub {
    test2_stack->top->filter(
        sub {
            my ($hub, $event) = @_;
            return if $event->diagnostics;
            return $event;
        },
        inherit => 1,
    );
});

1;