Follow-up to #2721. It fixes how the remaining tests behave and changes no production code.
## CI
- Both `dotnet test` steps pass `--filter "Category!=Manual"`. Before this, Manual-tagged tests ran on CI anyway.
- The one surviving movement-throttle latency test is the only coverage of burst forgiveness over a full, wrapped history. It loses its Manual tag, so it runs on CI.
## Tests that passed on CI without testing anything
- **Corpse and throwing tests.** They relied on tiledata for the weapon `Layer`, so on CI the equip silently failed and they asserted against empty lists. They now set `Layer` explicitly and assert the equip took effect. `TestThrown` also pins its own strength and range values, so a shard retuning SoulGlaive no longer breaks them.
- **Healthbar poison rows.** Server.Tests registers no poisons, so every row tested `null`. They now use real poison levels.
- **Account packet tests.** The mock accounts reported `Length` 0, so the character-list tests only ever encoded empty slots. They now encode the real characters.
- **Pathing and AI tests that only mean something on real Trammel/Felucca terrain** are now guarded with `TileDataRequirement.SkipIfMissing()`: Britain desk and clutter scenes, house footprints (no MultiData on CI) and fingerprints. Tests that are valid on flat blank terrain stay unguarded. (A synthetic tiledata fixture to run these on CI is a planned follow-up.)
- **Assertions that couldn't fail now check their claim.** Affected tests include the `DefaultWalker` cache use, cache on/off parity requiring a path, the recorder capability flags, the idle-pet gate, the monthly DST recurrence, the AdvancedSearch `Record.Exception` wrappers, `CanFitItem` with no branch-guarded assert, the Firewall callback, and `Import_NoMap`. The Geometry Parse asserts also now use the same input as their TryParse.
## Shared state
Every test that changes process-wide state now restores it, even when an assert fails:
- **The clock.** A new `TimerWheelScope` saves and restores `Core._tickCount`, `Core._now` and the timer wheel. `SimulatedClockScope` covers decay tests.
- **StepCache settings and caches**, via `StepCacheStateScope`.
- **Network state.** The ManualAllowlist, LoginAllowlist, firewall and BanChannel reporters are restored. Global packet handlers are now registered per test and removed afterwards, so they no longer stay registered for later tests.
- **Data and config tables.** `ArchiveJournal` statics, `TileData.ItemTable`, `ObjectPropertyList.Enabled`, `Core.Expansion` and the localization table are restored. One `MobileStatusVersion` restore was resetting a different expansion than the one the test changed.
- **Entities.** Tests with fixed serials now delete what they create. Fixed mobile serials moved to `World.NewMobile`, because deleting a hard-coded serial could unregister a live entity.
- **Collection race.** `SpiralScanTests` no longer clears the spawn cache from a separate collection that could run in parallel with the cache-manager tests.
- **Shared statics.** Classes reading shared static allowlists joined the sequential collection.
## Duplication
New shared helpers replace copy-pasted harness code:
- **Server.Tests:** `PacketAssert.Sends`, used by about 130 packet tests; `TestClientHarness`, `PersistencePipelineScope`, `NetTestHelpers`, `EntityCleanup` and one `TestMulti`.
- **UOContent.Tests:** `TimerWheelScope`, which also holds one wraparound-safe `RunFor`/`RunUntil`; `AiTestStubs`, which merges six walker copies and five identical creature stubs; `MobileTestHarness`, `CommandTestHarness` and `TempDirectory`.
Dead oracle packet classes are removed.
## Cost
| Test | Before | After |
|---|---|---|
| `VirtualSerialTests` | 1.57s | 2ms (starts near the wrap via reflection instead of drawing ~17.9M serials) |
| Event scheduler recurrence loop | 473ms | 1ms |
| CrowdSec drain | 517ms | 16ms (event-driven instead of a fixed 500ms wait) |
| AuthId tests | 248ms | 99ms (SHA2 except the two GameLogin tests) |
| Container cap tests | 5,000 items | 3,449 / 3,277 (one past each protocol cap) |
| Bulk removal | 100k children | 20k children |
| OPL hash distribution | 60k builds | 10k builds |
## Shard-tuning decoupling
- AI assertions read `ReacquireDelay` and `FollowMoveSpeed` instead of hard-coding production tuning.
- The guard friendly-fire test uses an `AI_Mage` stub instead of WhiteWyrm.
- Argon2 assertions pin the `argon2id` variant and `v=19` but read the cost parameters from the configured hasher.
## Tests
| Run | Server.Tests | UOContent.Tests |
|---|---|---|
| With client files | 812 pass | 1,123 pass |
| Without client files (CI simulation) | 800 pass, 12 skip | 1,021 pass, 102 skip |
- The UOContent fixture reads `MODERNUO_TEST_DATA_DIR`; Server.Tests reads `MODERNUO_CLIENT_PATH`.
- The 15 new UOContent skips are the map-dependent guards above.
- Total run time with client files is about 5s, down from about 8s.
## Why
Delta world saves (only changed entities re-serialized during the freeze) need two things from content: `Serialize` must be pure, and an unchanged entity must produce identical bytes on every save. An audit of the tree found the places that break this today. This PR fixes them and adds a diagnostic that measures byte stability in a running world over real time. No wire format changes, no version bumps.
## What
- **Guild**: `Serialize` ran the daily guildmaster recalculation (dictionary-order tie breaks, random picks, mutates another entity), war expiry, and the alliance leadership check on every save. That work now runs from `GuildMaintenanceTimer` (the former `WarTimer`, now started for both guild systems; the war and alliance checks are no-ops without the new guild system).
- **BaseHouse**: the `DecayLevel` getter wrote `LastRefreshed` and advanced the dynamic decay stage on every read, so any undecayable house changed its persisted bytes whenever a sign, gump, or `[Props` looked at it. It is now a pure read; `UpdateDecay()` on the decay tick advances the stage and refreshes a house that leaves the undecayable state.
- **Locked-down container contents decay through `DecayScheduler`** instead of a sweep inside `BaseHouse.Serialize`. `Item.CanDecay` now accepts a parent container whose new `Container.ContentsDecay` is true (locked down and not secure) when the content item is not itself locked down or secured; the `IsLockedDown`/`IsSecure` setters re-evaluate a container and its direct contents; `OnDecay` resolves the region from the world location. `BaseBoard`, `Aquarium` and `FishBowl` override `ContentsDecay` to false, matching the exclusions of the old sweep. Items already inside such containers are picked up at load, where every item re-evaluates its registration. The per-save O(all locked-down items) walk is gone; the work is now event driven.
- **BraceletOfBinding**: the `Bound` getter nulled its backing field for a deleted target; it now returns null for a missing or deleted target without writing.
- **`[SaveStability [delaySeconds=60] [sampleStride=1]`** (Administrator): hashes the serialized bytes of every entity in every registered entity persistence (`Persistence.EntityPersistences`, new), waits the delay in real time, hashes again, and reports per type how many records changed. Both passes are chunked under a 20 ms per-tick budget. Serializing twice inside one tick cannot see drift derived from `Core.Now`, which is frozen within a tick; the real-time wait is the point. On an idle shard the only legitimate churn is NPC movement and regeneration, so a static type with a high changed fraction is a serialization bug. `[SaveStability cancel` stops a run.
Engine additions: `Container.ContentsDecay` / `UpdateContentsDecayRegistration()`, the `CanDecay`/`OnDecay` change above, and diagnostic-facing `IGenericEntityPersistence.Name`, `EntityCount`, `EnumerateEntities()`, and `Persistence.EntityPersistences`.
## Behaviour notes
- Fealty recalculation now happens on the minute timer for both guild systems instead of at save time.
- A house that becomes decayable is refreshed on its next decay tick rather than at the exact moment of transition (at most one minute later).
- Contents of locked-down containers now decay on their own schedule (same `LastMoved + DecayTime` rule) instead of at the next world save after becoming due.
## Testing
- New tests: `GuildSerializePurityTests`, `HouseDecayPurityTests`, `SaveStabilityTests` (stable entities hash identically after the clock advances; a clock-stamped record is reported by type only after the clock advances; the snapshot covers Items, Mobiles and Guilds).
- `LockedDownContainerDecayTests` (Server.Tests): registration on drop, lock/secure/release transitions, excluded containers, nested containers, and decay on schedule through the scheduler.
- Full suites: Server.Tests 855 passed, UOContent.Tests 765 passed.
Kamron Batman