use warnings;
use strict;
use Test::More tests=>2;
use Test::NoWarnings;
use Test::Warn;

sub Foo::get_member_id_by_name { warn "foo than bar" };
my $obj = bless {}, 'Foo';

warning_like ( sub { $obj->get_member_id_by_name('smith'); },
	qr/than/, 'warns when more than one name returned' );

__END__

1..2
ok 1 - warns when more than one name returned
ok 2 - no warnings