Test suite validates optimization strategy that reduces N+1 query problem:
- Current: 6 queries per client (getCurrent + 5x getAgingAmount)
- Optimized: 1 query total using CASE statements
Test coverage:
- Data quality: 100% match between implementations (40 assertions)
- Edge cases: no invoices, deleted, zero balance, status filters
- Boundary testing: exact aging bucket boundaries (0,30,31,60,61,90,91,120,121 days)
- Performance: 60x query reduction for 10 clients, 6000x for 1000 clients
All 8 tests pass with 61 assertions.
Ready for production implementation.
David Bomba