> The author is advocating for mockist style of unit testing IMO: "mockist" style of unit tests are best for corner cases that can only be tested in isolation.

> The author is advocating for mockist style of unit testing IMO: "mockist" style of unit tests are best for corner cases that can only be tested in isolation. For example, error conditions that are important to verify, but so difficult or impossible to test that the only way to test them is to test a single class in isolation.