use Test::More 'no_plan';

BEGIN {
    if ($ENV{PERL_CORE}) {
        chdir('t') if -d 't';
        @INC = qw(../lib);
    }
}

BEGIN { use_ok('NEXT') };
my $order = 0;

package A;
@ISA = qw/B C D/;

sub test { ::ok(++$order==1,"test A"); $_[0]->NEXT::UNSEEN::test; 1}

package B;
@ISA = qw/D C/;
sub test { ::ok(++$order==2,"test B"); $_[0]->NEXT::UNSEEN::test; 1}

package C;
@ISA = qw/D/;
sub test { ::ok(++$order==4,"test C"); $_[0]->NEXT::UNSEEN::test; 1}

package D;

sub test { ::ok(++$order==3,"test D"); $_[0]->NEXT::UNSEEN::test; 1}

package main;

my $foo = {};

bless($foo,"A");

eval{ $foo->test }
	? pass("Correctly survives after C")
	: fail("Shouldn't die on missing ancestor");

package Diamond::Base;
my $seen;
sub test {
	$seen++ ? ::fail("Can't visit inherited test twice")
		: ::pass("First diamond is okay");
	shift->NEXT::UNSEEN::test;
}

package Diamond::Left;  @ISA = qw[Diamond::Base];
package Diamond::Right; @ISA = qw[Diamond::Base];
package Diamond::Top;   @ISA = qw[Diamond::Left Diamond::Right];

package main;

Diamond::Top->test;