> The entire team could read a changelist and know exactly what the consequences are; they could just read the diff and run the complete test suite in their head. So there was no need for them to spend the time actually typing in a test suite.
I think testing at Google is excessively complicated for a myriad of reasons, and the unit-test-style "coverage" doesn't really map well to how things work together in a larger system. That system-wide thinking is where the "read a code change and know exactly what's wrong" intuition becomes invaluable. *Integration* testing is especially hard for some reason (probably complexity in the serving stack, at least for many teams I've worked with), so you end up getting this pattern where people get better at other production health stuff like canary systems, release management, etc.
> The entire team could read a changelist and know exactly what the consequences are; they could just read the diff and run the complete test suite in their head. So there was no need for them to spend the time actually typing in a test suite.
I think testing at Google is excessively complicated for a myriad of reasons, and the unit-test-style "coverage" doesn't really map well to how things work together in a larger system. That system-wide thinking is where the "read a code change and know exactly what's wrong" intuition becomes invaluable. *Integration* testing is especially hard for some reason (probably complexity in the serving stack, at least for many teams I've worked with), so you end up getting this pattern where people get better at other production health stuff like canary systems, release management, etc.