In the case of that article, it doesn't matter whether you are using Struts2 or something else because you aren't testing the framework; just your logic. I like this approach. I test the framework through a browser. Either approach is feasible though.
When you are mocking you do hard code values. However the person writing this low level unit test is doing so at the same time as the code. It is on his/her mind.
I skipped the questions about how you'd test your code. As near as I can tell the code you are trying to test isn't in the
thread. And the thread is long. When posting for help, it is best to have short self contained examples so someone can easily read them and see what you are trying.