GitLab

Billing (25 tests):
- CalculateCostUnified: nil resolver fallback, token/per_request/image modes
- GetModelPricingWithChannel: nil/partial/full channel overrides
- resolveAccountStatsCost: four-level priority chain integration tests

WebSearch (18 tests):
- PopulateWebSearchUsage: nil input, manager states, QuotaLimit nil/*int64
- ResetWebSearchUsage: nil manager error
- Manager.ResetUsage: nil Redis
- shouldEmulateWebSearch: full decision chain (8 scenarios)

Notify (36 tests):
- ParseNotifyEmails/MarshalNotifyEmails: old/new format, roundtrip
- crossedDownward: boundary values, threshold semantics
- checkQuotaDimCrossings: mixed dimensions, disabled/zero skip