Testing is not the point. The point is about responsibility.
I don't like the feeling, but I've got to say that a little fear makes me a more focused, more responsible programmer.
I've known people who have not mastered their tools who are good programmers, but not a tool master who remained a mediocre programmer.
Make it work, make it right, make it fast.
If testing costs more than not testing, then don't test.
I mean, source code in files; how quaint, how seventies!