Creating a factory or fixture with id = 0

I know this is a bad design on my part, but I was wondering if it was possible to add a fixture or a factory to my tests with the id of 0, I have tried various methods but they don't seem to work. Maybe I will need to move to a non-active record for this model?

If you must know why I have a record that needs an id of 0 I originally had the table as an array (from a legacy php app) which is why the id of 1 exists.. I know it isn't good.

Cheers

Richard