With proper permissions, my code is unable to chdir; why?

gistfile1.txt

This one has me stumped.  

The user with which I am developing this owns that directory, 
and in a bash shell, has no issues whatsoever changing to that 
directory.  Yet somehow (driven from my test script), my module 
seems unwilling to make this change.  And as a consequence, my 
script is blowing up several lines later (thankfully) when it 
attempts to overwrite the site I want to update with the updated 
code.  

package MyApp.pm;

use Cwd qw( getcwd abs_path );
use Log::Log4perl;

<snip>

sub install_site {
  my $self = shift;
  my $args = shift;
  my $logger = get_logger('MyApp::install_site');
  print "Now running ->install_site \n";

    .  .  .  

  print Dumper( $args );
  print Dumper( $args->{'doc_root'} );
  my $doc_root = $args->{'doc_root'};
  print "doc_root: $doc_root \n";
  chdir $doc_root or warn "Unable to chdir to $doc_root \n";
  my $abs_path = abs_path( '.' );
  $logger->warn( "We've changed directory to: $abs_path " );
  print "Our directory is: $abs_path \n";

    .  .  .  

  return $app_id, $array_ref;
}

-----

t/013-this_test.t

my ($app_id, $array_ref) = $ymd_prov->install_site({
    site_id => 75,
    version => 6,
   doc_root => 't/conf/var/www/sites/update.test.example.com/',
     update => 1 });

-----

yields this output:

Now running ->install_site 
$VAR1 = {
          'version' => 6,
          'site_id' => 75,
          'update' => 1,
          'doc_root' => 't/conf/var/www/sites/update.test.example.com/'
        };
$VAR1 = 't/conf/var/www/sites/update.test.example.com/';
doc_root: t/conf/var/www/sites/update.test.example.com/ 
Unable to chdir to t/conf/var/www/sites/update.test.example.com/ 
Our directory is: /home/hesco/sandbox/MyApp/t/conf/var/www/sites/test.example.com