With continious integration (CI) one gives excellent locality in time/changesets. So I think the locality argument might not be as important today. Though I am

With continious integration (CI) one gives excellent locality in time/changesets. So I think the locality argument might not be as important today. Though I am biased, since I generally prefer to have tests that exercise more code, normally only against external APIs. Strong agreement on that pre/post-condition/invariants are highly useful though. I prefer that they are enabled also in production code, except for in the hottest of codepaths.