Tests for lineage metrics.

[phixMe]

One-line summary: Improve test coverage for lineage metrics

Checklist

• [x] You've signed-off your work
• [ ] Your changes are accompanied by tests (if relevant)
• [ ] Your change contains a small diff and is self-contained
• [ ] You've updated any relevant documentation (if relevant)
• [ ] You've included a one-line summary of your change for the CHANGELOG.md (Depending on the change, this may not be necessary).
• [ ] You've versioned your .sql database schema migration according to Flyway's naming convention (if relevant)
• [ ] You've included a header in any source code files (if relevant)

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[phixMe]

@wslulciuc The test harness is displeased by two extensions of the DbTest class. Probably something to fix in an overall capacity.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 83.10%. Comparing base (9450410) to head (0580676). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2894 +/- ## ============================================ + Coverage 82.97% 83.10% +0.13% - Complexity 1485 1487 +2 ============================================ Files 264 264 Lines 6849 6849 Branches 315 315 ============================================ + Hits 5683 5692 +9 + Misses 1011 1002 -9 Partials 155 155 ```

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[wslulciuc]

PR #2894 - Test Suite for OL events stats