As always in these discussions I like to remind everyone that you can have good and bad implementations of everything, and just doing unit testing doesn't make

As always in these discussions I like to remind everyone that you can have good and bad implementations of everything, and just doing unit testing doesn't make your engineers suddenly understand how to write testable code. So, you can well end up in a situation with a reasonable amount of code coverage, but not quite as high as you might like and when someone invariably digs into why they find while parts of the system are testable, parts of the system aren't. Now you're left with a large test suite that provides marginal value because it doesn't give you confidence your code can be deployed if just because it's passing, but the shite engineering practices heavily test implementation details which make maintenance slow to a crawl. Good engineering is what creates good engineering. What you actually do, I suspect matters a lot less.