I think it depends on whether your users can write programs for your program. I work on a web browser, and every test is worth something. To some degree, we do

I think it depends on whether your users can write programs for your program. I work on a web browser, and every test is worth something. To some degree, we don't care what the test is testing. We want to be sure we don't change it unintentionally, thus breaking the web.