Consider using Test::Mock or mock directly; you need to test your stuff, not theirs

Thanks, I shall have a look at that for future reference.

The solution I am trying is described over here -> Re^6: [RFC] Module code and POD for CPAN - Testing and test file

If I can get that to work then I feel it will be preferable as the end user doesn't have to install any more modules than necessary. Business::Stripe::WebCheckout has deliberately been written to only use core modules so it is easy to use on restrictive shared hosting.