I have developed two web services. The main service is a RESTful service (using DB), and another UI service that uses the RESTful service.

Say I want to test the UI for now (integration tests), every test will makes changes in the prod DB. More then that, if in the RESTful service, there are one-way functions for security reasons. I mean that functions that can not be revert (Say if mark item as 'done', I can't edit or delete it anymore)?

This things are very logical, the most websites I know have the same situation. All these websites are not testable?