Change behavior of expectation overrides to strictly override.
Created attachment 101331 [details] Patch
Dirk, wanted you to see this. Even though it relaxes the grip of tidiness on the downstream test_expectations.txt, this division between "insert" and "update" will make for much more straightforward TestExpectationModel code.
Comment on attachment 101331 [details] Patch Hm. I'm not convinced this is a win, since it will allow us to generate what would be (IMO) buggy overrides files that do contain duplicates that we wouldn't notice. Perhaps there is another way to do this, that would distinguish when you were parsing a block of updates that needed to be self-consistent from when you were updating entries one at a time, and you did want the last-one-wins behavior?
Sounds like we need more discussion here.
Per further discussion w/ dimitri, I can see how if we create an object that manages the "view" (in the database sense, not the MVC sense) that can deal with lines as a set, we can pull this logic out of here. This change will potentially break things in the short term (since you can put overrides in with duplicates that won't be caught) but the risk of this seems low.
Comment on attachment 101331 [details] Patch Turns out I don't need this.