From the paper: "Throw away tests that haven’t failed in a year." Hell, no. Our unit tests provide reassurance that when somebody revisits a component N years

From the paper: "Throw away tests that haven’t failed in a year." Hell, no. Our unit tests provide reassurance that when somebody revisits a component N years from now, and makes a change, they are significantly less likely to break the existing behaviour, even subtly. Throwing away unit tests is like saying "This ship has been sailing for years and has never sunk - let's throw away the lifeboats!" Now, yes - somebody could erroneously change the test condition to make it pass, although hopefully that kind of change would be spotted by even a cursory code review. You can say the same thing about developers who carelessly suppress compiler warnings without understanding what they're telling them. However, the support is there in case I, or another developer, make a mistake. FWIW, catching future mistakes is definitely not the only thing for which we use Unit Tests. The problem domain is hard, and for every test fixture we've written we've found at least one bug. Catching and debugging these bugs from the unit test runner is a lot easier than spotting and debugging these kinds of issues at runtime.