package Sub::Class;
use base 'Super::Class';

sub public_setCreditAmount { shift->setCreditAmount(@_) }

##</code><code>##

# in the test script
{
  package Sub::Class;
  our @ISA = 'Super::Class';
  my $got;
  eval { $got = $obj->setCreditAmount( @argument ) };
  is( $@, q{}, "setCreditAmount called as subclass" );
  is( $got, $expected, "setCreditAmount return value correct" );
}