Testing is important, because there are many ways things can go wrong.
Automated testing is critically important, because "manual testing" is often another phrase for "testing we plan to do but won't do often if ever".
Unit testing may or may not be the best approach. Unit tests are fast, and make it easy to answer very specific answers, but they're tied to the specific software design. Since computers have become much faster, I generally recommend that people use more integration testing, because they reveal when the components fail to work together (for whatever reason), and their added CPU effort is typically no big deal.
That said, I agree that testing is only useful if it's plausible it would detect a problem. But developers are really good at asserting something "can't happen" and then does :-).
Automated testing is critically important, because "manual testing" is often another phrase for "testing we plan to do but won't do often if ever".
Unit testing may or may not be the best approach. Unit tests are fast, and make it easy to answer very specific answers, but they're tied to the specific software design. Since computers have become much faster, I generally recommend that people use more integration testing, because they reveal when the components fail to work together (for whatever reason), and their added CPU effort is typically no big deal.
That said, I agree that testing is only useful if it's plausible it would detect a problem. But developers are really good at asserting something "can't happen" and then does :-).