Unit testing is a development practice that is viewed as a "must do" by more and more programmers and experts. And yet, I think that unit testing is much less mandatory on smaller teams, non-API/framework development, and for certain types of code (anything non-deterministic comes to mind).
I'm not saying that unit tests are unimportant or useless, but I do think that their usefulness is often overstated, and that they have differing levels of utility to different developers.
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Justin James is the Lead Architect for Conigent.