This is a people problem as much as a test problem. 1. Write your code so that independent units of functionality (algorithms) can be tested. 2. Make sure peop

This is a people problem as much as a test problem. 1. Write your code so that independent units of functionality (algorithms) can be tested. 2. Make sure people understand, when changing code, either a) change the tests first, or b) recognize what tests should be failing because of the change and which shouldn't. For good, testable code combined with good tests, it should be rare that the tests start failing when you change the implementation. Admittedly, that's true in theory and can vary widely in practice.