--- /dev/null
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More tests => 9;
+use Test::Exception;
+
+{
+ package Animal;
+ use Mouse;
+ use Mouse::Util::TypeConstraints;
+
+ subtype 'Natural' => as 'Int' => where { $_ > 0 } =>
+ message {"This number ($_) is not a positive integer!"};
+
+ subtype 'NaturalLessThanTen' => as 'Natural' => where { $_ < 10 } =>
+ message {"This number ($_) is not less than ten!"};
+
+ has leg_count => (
+ is => 'rw',
+ isa => 'NaturalLessThanTen',
+ lazy => 1,
+ default => 0,
+ );
+}
+
+lives_ok { my $goat = Animal->new( leg_count => 4 ) }
+'... no errors thrown, value is good';
+lives_ok { my $spider = Animal->new( leg_count => 8 ) }
+'... no errors thrown, value is good';
+
+throws_ok { my $fern = Animal->new( leg_count => 0 ) }
+qr/This number \(0\) is not less than ten!/,
+ 'gave custom supertype error message on new';
+
+throws_ok { my $centipede = Animal->new( leg_count => 30 ) }
+qr/This number \(30\) is not less than ten!/,
+ 'gave custom subtype error message on new';
+
+my $chimera;
+lives_ok { $chimera = Animal->new( leg_count => 4 ) }
+'... no errors thrown, value is good';
+
+throws_ok { $chimera->leg_count(0) }
+qr/This number \(0\) is not less than ten!/,
+ 'gave custom supertype error message on set to 0';
+
+throws_ok { $chimera->leg_count(16) }
+qr/This number \(16\) is not less than ten!/,
+ 'gave custom subtype error message on set to 16';
+
+my $gimp = eval { Animal->new() };
+is( $@, '', '... no errors thrown, value is good' );
+
+throws_ok { $gimp->leg_count }
+qr/This number \(0\) is not less than ten!/,
+ 'gave custom supertype error message on lazy set to 0';
+