This test is for the issue discussed in the PM post:

http://www.perlmonks.org/index.pl?node_id=516372

The errors which were reported were:

Use of uninitialized value in split at
  /usr/local/share/perl/5.8.4/UNIVERSAL/can.pm line 51.
Called UNIVERSAL::can() as a function, not a method at
  /usr/local/share/perl/5.8.4/Class/DBI.pm line 265
Can't call method "can" on an undefined value at
  /usr/local/share/perl/5.8.4/UNIVERSAL/can.pm line 40.

Class::DBI line 265 is:

255 > my @pk_values = $self->_attrs($self->primary_columns); 265 > UNIVERSAL::can($_ => 'id') and $_ = $_->id for @pk_values;

In all likeliness Class::DBI line 265 really should be:

eval { $_->can( $_ => 'id') } and $_ = $_->id
  for grep { defined $_ } @pk_values;

or something similar to prevent sending an undefined value to UNIVERSAL::can.

However, in the interest of making this module as useful as possible, it should check for bad input and DWIM in those cases.