This task is done when coverage of ORES extension is above 60%, current value: 38%: https://doc.wikimedia.org/cover/extensions/ORES/index.html
Classes needing the most tests:
- ChangesListHookHandlers
- HashModelLookup: https://gerrit.wikimedia.org/r/402486
- FetchScoreJob: https://gerrit.wikimedia.org/r/402485
- Hooks
- WatchedItemsQueryServiceExtension
Api class also lacks tests but I'm planning to rewrite the class from scratch.