[roel_v]

If you're the new hire and the first you you're doing is pester everyone with extra work they don't see the advantage of - that'll just get you the reputation of a know it all, in my experience. That's why I suggested to start chipping at it on his own, so that he can show the value a few months down the line, rather than telling everyone how great it's going to be when he's not respected yet or hasn't proven himself yet. But that's also what I meant by 'it's not a technical issue'. It's a matter of positioning himself as a reliable person whose opinion on technical matters needs to be considered. New hires generally aren't, unless they have an impressive resume or reputation before they started at the company. But someone like that doesn't ask this question to a bunch of strangers on the internet.

Of course it depends on the circumstances. If you're on your own trying to maintain a test suite on the code of 50 other people, none of whom work on these tests and think you're just trying to slow them down for no good reason, there's no way that will work. But if there's only a few people working on the code and you can maintain tests for a more or less well defined part of it - it's possible (if you're experienced enough; if you have to spend 2 weeks reading up on how to do unit testing, it's not a viable strategy of course.)