You're agreeing with me there. "each one exercising a little piece of functionality". In Beck's approach the tests are added at each step for a simple functionality addition, which then gets implemented in the project to pass the test. These days unit tests are more commonly used as "every method is a unit to be tested completely", often after the implementation is already there.

I don’t see how?

You said: “Around the xp times, unit tests were not per-method.”

Beck said: “Unit tests are usually individual methods”