test: add unit tests for root owners finding

[codecov[bot]]

Codecov Report

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

Comparison is base (18eff73) 29.49% compared to head (3ae9f3f) 30.11%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #80 +/- ## ========================================== + Coverage 29.49% 30.11% +0.61% ========================================== Files 22 22 Lines 1624 1624 ========================================== + Hits 479 489 +10 + Misses 1098 1086 -12 - Partials 47 49 +2 ```

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