[spc476]

> But tests as a way of preventing unknown issues seems dubious to me.

True. At my previous job, I used a new C compiler [1] that revealed a bug due to undefined behavior [2]. It was a two-line fix, but my manager at the time refused to accept the fix unless I 1) made a test that showed the error, and 2) write tests to show other instances of this type of bug. The test would have been useless since I used an unsanctioned C compiler, and (due to the nature of the bug) I'm not sure if static analysis would have found the bug anyway.

[1] Test driving the latest Ubuntu Linux installation for development.

[2] The code worked as expected on the business-supported C compilers (it's undefined behavior, anything can happen). Even valgrind didn't catch the error (we were using that at the time) because of the way the code was generated.