zlacker

That's exactly why you write tests. You want to be sure future changes don't break present functionality, especially if the future changes are being done by someone who doesn't understand your part of the system.

>>onion2+(OP)
But if you need to make an update to a core system that'll necessitate updating the tests and you're back to flying blind.

>>Sketch+7S
It shouldn't require updating the tests, so long as you're testing the functionality rather than the implementation.

>>onion2+(OP)
You write tests for your code as it exists to make sure it functions. You cannot write tests for every conceivable change that someone else might make in the future that either mis-uses your code or adds new code inbetween that didn't previously exist. You need the people who add that new code to write new tests. Something that it seems the remaining engineers at Twitter do not have time for.