[bvrmn]

> I've seen 100% code coverage with tests for all the getters and setters. These tests were not only 100% useless, they actively hindered any changes to the system.

It's a red flag to blame high coverage for fragile tests. Use narrow public component interfaces to reach code parts and you simultaneously gain robust tests which can be used during refactoring and you can be guided by coverage to generate test cases. Bob Martin has a great article: https://blog.cleancoder.com/uncle-bob/2017/10/03/TestContrav...