Writing tests for nearly all my code, in particular, is these days the only way I roll - and as for TDD (i.e. write the test and let it fail first, then write the actual code and make the test pass), I do it quite often, and I guarantee you that - contrary to your opinion - it makes coding a whole new kind of fun and creative. Dependency injection I still consider myself less of a ninja at, but I've done it (and seen it done) enough times now that I get it and I see the value in it.
I think it's a bit stupid for an employer to say "we'd never have hired you if we knew you had no experience in X" (sure, this doesn't apply to all skills, but I'd say it applies to quite a few). If you're worth hiring, then you'll pick up X within a few months on the job. I'm grateful to several past employers of mine, for showing me the ropes of TDD and DI (among many other things).
Anyway, I'm not saying that the above things are "the (only) right way to do it", and please don't take my above ramblings as making a judgement on your coding prowess. I agree, do what works for you. I'm just saying that there's always more to learn, and that you should always strive to be open-minded to new skills and new approaches.