As reported by https://doc.wikimedia.org/cover-extensions/CheckUser/src/Investigate/index.html, the code coverage over Investigate related code is low.
Increasing it is important to ensure that the large changes needed to implement T329189: Add read new support to Special:Investigate for event table migration do not cause a Regression.
Acceptance criteria
- Test coverage listed at https://doc.wikimedia.org/cover-extensions/CheckUser/src/Investigate/index.html is largely marked as covered, especially in the Services and Pagers folders