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.
## The bug
`ObjectPropertyList.AddHash` folded each cliloc and a Marvin hash of each argument together with XOR, which is both commutative and self-inverse. Any value mixed in an even number of times cancelled outright, so two properties sharing one argument hashed identically no matter what that argument was:
```
_hash = 31659021
AddHash(1063752); AddHash(hash("10"))
AddHash(1063737); AddHash(hash("10")) // the argument cancels here
AddHash(1063740) // -> 32714560, for ANY argument
```
The 10% and 5% variants of the same item therefore produced the same revision. The client caches the tooltip by revision and only re-requests when it changes, so it kept rendering the stale percentage.
Same root cause, three more shapes:
| | old | new |
|---|---|---|
| Two properties sharing an argument | collides | distinct |
| Properties reordered | collides | distinct |
| Two properties trading arguments | collides | distinct |
| Argument-less property added twice | cancels to 0 | distinct |
## The fix
Hash the finished property block in `Terminate()` instead of accumulating per property. Those bytes — cliloc, length prefix and UTF-16 text, in emission order — are the exact content the client renders, so anything that changes the tooltip changes the hash. The length prefix also removes the concatenation ambiguity the old scheme had.
`AddHash` and both `string.GetHashCode` calls are gone.
## Why 26 bits, and why not 64
The client never recomputes the hash — it stores what we send in 0xD6 and compares it for equality against the 0xDC revision (`ObjectPropertiesListManager.IsRevisionEquals`). So the algorithm is ours to choose, but the width is not:
- Both packets carry a **4-byte** revision, so 64 bits is not available. A wider internal value would be worse than useless: the server would see a change and send a 0xDC whose truncated 32 bits are identical, and the client still wouldn't refresh.
- `Terminate` writes the bare hash into 0xD6 while `SendOPLInfo` writes `Hash` with bit 30 set. The client recovers one from the other by masking off `0x40000000`, which only holds while the hash stays below that bit. Hence 26 bits, unchanged from before.
- `Hash => 0x40000000 + _hash` keeps the revision non-zero; the client parks 0 as its "nothing cached" sentinel.
## Collision behaviour
Enumerated real small-OPL spaces and counted 26-bit collisions against the birthday expectation for a uniform hash:
| Scenario | block | n | collisions | expected |
|---|---|---|---|---|
| 1 cliloc, no arg (every cliloc 1.0M–3.2M) | 6 B | 2,200,000 | 35,591 | ~36,061 |
| 1 cliloc + numeric arg 0–199,999 | 8–12 B | 200,000 | 300 | ~298 |
| 2 clilocs, both with numeric args | 12–24 B | 202,500 | 288 | ~306 |
| 1 cliloc + 1-char arg | 8 B | 4,000,000 | 116,291 | ~119,209 |
Every case lands on the random-model line, and per-bit P(1) across all 26 bits is 0.4962–0.5024 — XXH3's short-input paths still avalanche fully, so a 6-byte block behaves like a uniform 26-bit draw. Masking the low 26 bits versus folding all 64 down was a wash (35,591 vs 35,558).
The metric that matters is narrower, since the client compares a revision only against the previous revision **for the same serial**: 2^-26 = 1.5e-8 per genuine tooltip change. Consecutive-value transitions (charges 50 -> 49) collided 0 times in 200,000.
Row 3 is the old scheme quantified: it collapsed 202,500 inputs into 100,954 distinct hashes, a 50% collision rate — systematic, not probabilistic.
One honest regression: in row 1 the old scheme had zero collisions, because for a single argument-less cliloc under 2^26 the hash was the identity function. An item whose whole tooltip is one argument-less cliloc changing to a different one goes from never colliding to 1.5e-8.
## Performance
Cheaper, not just correct — one xxHash3 pass replaces a Marvin hash per string property over those same bytes. A 12-property, 302-byte tooltip, steady state:
```
old (XOR + Marvin per property) 70.5 ns
xxHash3 (streaming, HashUtility) 27.0 ns
```
`XxHash3.HashToUInt64` one-shot is a further ~7ns faster and produces byte-identical output, but taking it would mean editing `HashUtility.ComputeHash64`, whose values are baked into save files via `AssemblyHandler.GetTypeHash`. Not worth it.
## Second commit: plant old-client property list
Found while tracing the `Hash` read sites. `PlantItem.OldClientPropertyList` called `InitializePropertyList` on every access instead of only when the list was null, and without a `Reset`. Every read appended another copy of every property to the same buffer. `SendOPLPacketTo` and `SendPropertiesTo` both go through the getter, so a pre-7.0.12 client looking at a plant grew the buffer without bound and moved the revision on reads alone.
Now builds once, matching `Item.PropertyList`. `InvalidateProperties` already `Reset`s before rebuilding.
## Testing
`Server.Tests` 869 passed, `UOContent.Tests` 779 passed.
New regression tests, each confirmed failing against the old code first:
- `RepeatedArgument_DoesNotCancelOut` — the reported case
- `PropertyOrder_ChangesHash`, `SwappedArguments_ChangeHash`, `DuplicateProperty_ChangesHash`
- `ShortNumericArguments_ConsecutiveValuesDiffer`, `SmallPropertyBlocks_StayWellDistributed` — short-input avalanche, bounded loosely enough to hold for any seed
- `Hash_StaysWithinTheRevisionMask`, `EmptyList_IsNonZeroAndDistinctFromPopulated` — wire constraints
- `PlantItemPropertyListTests.OldClientPropertyList_BuildsOnceAndIsStableAcrossReads`
Kamron Batman