use Test::More;
use strict;
use warnings;

{
    package My::Gearman::Client;
    use parent 'Gearman::XS::Client';

    sub foo {}
}

my $gm = My::Gearman::Client->new;

isa_ok($gm, 'Gearman::XS::Client'); # Pass
isa_ok($gm, 'My::Gearman::Client'); # Fail
can_ok($gm, 'foo'); # Fail