How about this:

#!/usr/bin/perl

use lib 'lib';

use strict;
use warnings;

use MyHolder;
use Moose::Autobox;
use Test::More tests => 6;

BEGIN { use_ok( 'MyHolder' ); }

my $cup_holder = MyHolder->new();

# name
$cup_holder->name("cupboard");
is ($cup_holder->name(), "cupboard",
   "name of cup holder should be cupboard");

# things
my @cups = qw(blue green green yellow);
$cup_holder->things(\@cups);
is ($cup_holder->things->length, 4, "there should be four things in th
+e cupboard");

# add an element to the array
$cup_holder->things->push("red");
is ($cup_holder->things->length, 5, "there should be five things in th
+e cupboard");

# remove the last element from the array
my $thing = $cup_holder->things->pop;
is ($cup_holder->things->length, 4, "there should be four things in th
+e cupboard");
is ($thing, "red", "the cup should be red");
[download]

which gives

$ prove -v
t/test_holder......
1..6
ok 1 - use MyHolder;
ok 2 - name of cup holder should be cupboard
ok 3 - there should be four things in the cupboard
ok 4 - there should be five things in the cupboard
ok 5 - there should be four things in the cupboard
ok 6 - the cup should be red
ok
All tests successful.
Files=1, Tests=6,  3 wallclock secs ( 0.01 usr  0.00 sys +  2.52 cusr 
+ 0.03 csys =  2.56 CPU)
Result: PASS
[download]

Or you could make 'things' have type Object::Array instead of 'ArrayRef', for similar results but without autoboxing.