Hey Programmingeek,
Welcome and thank you for joining the community, we're happy to have you here and look forward to your contributions. You bring up a really great question regarding certification.
Authorize.Net wants to do all that we can to support third-party solutions and developers that integrate to our gateway. We offer both our technical and channel resources to foster partnering opportunities. The certification program is quite simple. During the certification process we look at the Authorize.Net APIs that you have integrated. Based on your target market (card-not-present ecommerce or card-present) we ask you to provide transaction Test Cases for the market type. If your app can be used by merchants in both market types, you'll need to fulfill the requirements for each market type. You can expect to provided us with at least four test transactions for both e-commerce and card-present certification.
Because we are only testing your integration to Authorize.Net APIs there is no need for us to install the shopping cart or application and it does not make a difference if the app is running in a Windows or Linux environment.
Thanks,
Daryn