[MoreQARespect]

>The most insightful point is how testing fundamentally changes your design for the better. When you have to make something testable.

When people say this type of thing I consider it to be kind of a code smell that they're testing at too low a level and tightly coupling their tests to their implementation.

It is true that the pain of tightly coupling your code to your tests to your implementation can drive you to unwind some of that tight coupling but that still leaves your tests and your code tightly coupled.

I find the best bang for my buck are tests that are run at a high enough level to make it possible to refactor a lot and safely with a minimum of test changes. Technical debt that is covered by tests doesnt compound at nearly the same rate.