GSD Adversarial Review Pattern After implementing analytics functions that handle sparse or missing data, run a focused adversarial review on the exact diff before pushing. Specifically: (1) verify test assertions match the actual filter logic (not just fixture coincidence), (2) check for silent failures where data passes validation but shouldn't, (3) re-run full test suite after fixes. This catches TDD precision errors where tests accidentally pass on incomplete fixtures but would fail on real data. ---