I am not entirely sure it will work, (the effort to write the unittests is high) and there is little understanding of the codebase it will enter and the code reuse issue is ...
Add to that integration and delivery and this unittest approach is a problem.
But change it to be "here is our code and CI on github", create a pull request that will change the flow of the credit card processing to use swipe and paypal as well as our tired old merchant bank.
People could bid for the project, and so forth.