use Test::YAML tests => 4;      # subclass of Test::Base
     
     filter {
         yaml => 'load_obj',
         perl => 'dump_obj',
     };
     
     run_is yaml => 'perl';
     run_is perl => 'yaml';
     
     __DATA__
     === A hash
     --- perl
     { foo => 'bar'}
     --- yaml
     foo: bar
     
     === An array
     --- perl
     [ 2, 4, 42 ]
     --- yaml
     - 2
     - 4
     - 42