[crdoconnor]

>System level integration tests also tend to be more flaky.

That's usually a sign that they've been engineered poorly or you have bugs in your code.

System level integration tests need appropriate environmental isolation and solid asynchronous & multithreaded code. Nobody can be bothered to write these properly for tests, hence the flakiness ("ooh let's just insert a sleep here" / "eh, does it really matter which version of postgres we run?").