No subtests run

Hi,

Can anyone give me a reason that I should be getting "No subtests run" 
errors in reports such as:

http://www.cpantesters.org/cpan/report/93d15444-e665-11e1-9066-3d54fb7543f5

Equally puzzling is why only *some* test files are afflicted (and always the 
same files), but others are not.

For a quick link to compare the files, one of the "problem" files 
(overload_int.t) is here:
http://search.cpan.org/src/SISYPHUS/Math-Decimal64-0.02/t/overload_int.t

and one of the "trouble-free" files (overload_spaceship.t) is here:
http://search.cpan.org/src/SISYPHUS/Math-Decimal64-0.02/t/overload_spaceship.t

Cheers,
Rob 

• No subtests run by Sisyphus