use strict;
use warnings;
use Test::More;
use Test::Fatal;
{
package Foo;
use Moose;
use MooseX::Method::Signatures;
method foo ($bar) { $bar }
}
my $o = Foo->new;
is(exception { $o->foo(42) }, undef);
like(exception { $o->foo(42, 23) }, qr/Validation failed/);
done_testing;