I partially agree with the author, I think unit tests are great to ensure functions and methods are working correctly, and they have saved me a few times! Howe

I partially agree with the author, I think unit tests are great to ensure functions and methods are working correctly, and they have saved me a few times! However, here is my perspective from a hardware point of view: I think teams can be to quick to "mock" away real hardware from functional tests, and this can lead to hard to track bugs with communication. For example, on a project I worked on there was a bluetooth device and phone app. The team created a simulated device inside the app which mocked all communication. Things worked ok... until they didn't! What they should have done from the beginning is create the mocks on a "real" device and keep the Bluetooth communication in integration and functional tests. Bluetooth is a notorious pain in the neck but this is true for any external device or service. A mature project should have tests at multiple levels, from unit up to system level integration tests. The more integration you can provide developers the better, because then the surface area of untested hardware and software is smaller.