You always say “double-clicking a button” here, “paste too much information” there.
So we’re talking only about UI-development? Good, because I successfully use unit-testing for our product that is mostly running on the server-side without any UI to be used.
If you have clear interfaces a unit-test is the perfect tool to check if your implementation is fitting the description. If you implement the test at the same time like the implementation of the interface, it’s not taking much more time than the pure implementation (it’s growing with the implementation itself) and it can already tell you during the time of the production of the whole system (maybe including an UI) if something is now broken after e.g. an optimization of a part of the system.
Why should I start a testing of the functionality of an UI if I know that the underlying functionality is broken?
Unit-testing is the way I can ensure that a specific functionality is working without the need of an UI to be able to start that functionality anyway. So if a later implemented UI using this functionality is reporting an error it’s more likely to find the bug within the UI than the server-code doing the work.
Best regards, Lothar