> My approach prefers extracting IO operations to adapters, testing them separately, then using reliable fakes to test the bulk of the system’s behavior from th

> My approach prefers extracting IO operations to adapters, testing them separately, then using reliable fakes to test the bulk of the system’s behavior from the outside ...which is exactly a unit test. If you want to talk about "functional core, imperative shell" and its implications for tests, then do _that_. Writing clickbaity titles that directly contradict the content of your short blog post itself isn't a great way to foster nuanced discussion.