xref: /openbsd-src/gnu/usr.bin/perl/t/mro/next_method.t (revision 898184e3e61f9129feb5978fad5a8c6865f00b92)

#!/usr/bin/perl

use strict;
use warnings;

require q(./test.pl); plan(tests => 5);

=pod

This tests the classic diamond inheritance pattern.

   <A>
  /   \
<B>   <C>
  \   /
   <D>

=cut

{
    package Diamond_A;
    use mro 'c3';
    sub hello { 'Diamond_A::hello' }
    sub foo { 'Diamond_A::foo' }
}
{
    package Diamond_B;
    use base 'Diamond_A';
    use mro 'c3';
    sub foo { 'Diamond_B::foo => ' . (shift)->next::method() }
}
{
    package Diamond_C;
    use mro 'c3';
    use base 'Diamond_A';

    sub hello { 'Diamond_C::hello => ' . (shift)->next::method() }
    sub foo { 'Diamond_C::foo => ' . (shift)->next::method() }
}
{
    package Diamond_D;
    use base ('Diamond_B', 'Diamond_C');
    use mro 'c3';

    sub foo { 'Diamond_D::foo => ' . (shift)->next::method() }
}

ok(eq_array(
    mro::get_linear_isa('Diamond_D'),
    [ qw(Diamond_D Diamond_B Diamond_C Diamond_A) ]
), '... got the right MRO for Diamond_D');

is(Diamond_D->hello, 'Diamond_C::hello => Diamond_A::hello', '... method resolved itself as expected');

is(Diamond_D->can('hello')->('Diamond_D'),
   'Diamond_C::hello => Diamond_A::hello',
   '... can(method) resolved itself as expected');

is(UNIVERSAL::can("Diamond_D", 'hello')->('Diamond_D'),
   'Diamond_C::hello => Diamond_A::hello',
   '... can(method) resolved itself as expected');

is(Diamond_D->foo,
    'Diamond_D::foo => Diamond_B::foo => Diamond_C::foo => Diamond_A::foo',
    '... method foo resolved itself as expected');