I learned a lot reading this; in particular the discussion about fragility as it relates to using test-doubles for some collaborators and not for others in a single test instance. However, I absolutely love your conclusion hook as it validates (most of) my testing worldview.<p>I only say "most of" because I have rarely worked on a team where maximally realistic tests were anything but slow/fragile monstrosities that became stale very quickly.<p>I <3 isolation testing :)