--- /dev/null
+use strict;
+use warnings;
+
+use Test::More tests => 1;
+
+use Moose::Util::TypeConstraints;
+
+
+eval { Moose::Util::TypeConstraints::create_type_constraint_union() };
+
+like( $@, qr/\QYou must pass in at least 2 type names to make a union/,
+ 'can throw a proper error without Moose being loaded by the caller' );