FYI, I was trying to use Test::MockObject with mod_perl2, but discovered a bug that causes an apache2 child segmentation fault after several successful HTTP requests when running a shell command from the response handler (such as with backticks or system()). Here is a minimal response handler that reproduces the problem:

#! /usr/bin/perl -w

package MyApache2::Chain;
use strict;
use Apache2::Const -compile => qw(:common);
use Apache2::SubRequest ();       # for $r->internal_redirect

### Comment out the following line and the Apache2 child
### segmentation fault no longer occurs:
use Test::MockObject;

sub handler
{
my $r = shift || die;
my $f = $ENV{DOCUMENT_ROOT} . "/date.txt";
system("date >> $f 2> /dev/null");
$r->internal_redirect("/date.txt");
return Apache2::Const::OK;
}

##### DO NOT DELETE THE FOLLOWING LINE!  #####
1;
[download]

See my bug report at https://rt.cpan.org/Public/Bug/Display.html?id=73723