UI testing tools like Selenium and Sakuli can be used to automate testing of web and desktop applications. Sakuli builds on Selenium and adds capabilities for native desktop recognition using images. Tests can be run on containers for scalability. Sakuli examples show how to test a web app, validate a PDF, and control both web and rich clients by ordering in a web app and validating reports in a desktop client. Containers, Kubernetes, and tools like Skaffold and Jenkins can help implement continuous testing in a repeatable and scalable way.