The goal: Make the data clean up process automatic. The data should be cleaned up without an explicit call to a clean up function, and it should work even if the test script dies half-way through.

The solution: As part of creating the test data, keep track of the IDs of the data created in a package-scoped array. Use an END {} block to call the cleanup function, using the the package-scoped array to know what to clean up. The END block gets called when the script is exiting, even if it is "die"'ing.

Some example pseudo-code:

our @IDS_TO_DELETE;
sub create_test_widget {
   my $widget = Widget->new;
   push @IDS_TO_DELETE, $widget->id;
   return $widget;    
}

sub delete_test_widgets {
   for my $id (@IDS_TO_DELETE) {
       Widget->delete($id);
  }
}

END { delete_test_widgets(); }
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There you have it. Now just by creating some test data, it will automatically be removed when test is finished. I suggest putting a pair of functions like this in a private testing module and then importing the test data creation function.