The test suite lacked coverage for four critical paths: corrupt/null-
deserializing PayloadJson rows, StartDrainLoop timer behavior and backoff
honoring, concurrent EnqueueAsync+DrainOnceAsync stress, and the
outcomes.Count != events.Count cardinality-mismatch branch.
Added tests covering all four gaps (committed across companion findings):
- Drain_with_corrupt_payload_row_deadletters_it_and_keeps_good_rows_aligned
- Drain_with_corrupt_head_row_does_not_stall_queue
- StartDrainLoop_honors_backoff_and_slows_cadence_under_retry
- StartDrainLoop_keeps_steady_cadence_when_writer_is_healthy
- StartDrainLoop_records_drain_fault_and_keeps_running
- Concurrent_enqueue_and_drain_do_not_throw_sqlite_busy
- Writer_returning_wrong_cardinality_outcomes_sets_backing_off_and_keeps_rows
- Capacity_eviction_increments_evicted_count_on_status
- GetStatus_snapshot_is_consistent_under_concurrent_drain
Updated Open findings count to 2 (Core.AlarmHistorian-008 + -011, both Low).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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