I understand your example and I agree that in that particular case, maybe a unit test to ensure a given service calls a dao once and only once or whatever is ju

I understand your example and I agree that in that particular case, maybe a unit test to ensure a given service calls a dao once and only once or whatever is justified but I don't think the hypothetical risk of someone needlessly calling the db ten times is a good reason to justify adding that style unit tests to everything by default - if it happens, sure, add one for that particular call and call it a day