## Summary
Many tests proved a specific change when it landed but don't need to run on every CI build forever. This removes **202 test methods and 9 files: 313 test cases, 2,247 → 1,934**. UOContent.Tests drops from about 14s to about 5s locally.
Removed:
- **Tautologies.** Asserting a constant, a constructor readback or a trivial getter, or testing BCL behavior.
- **Exact duplicates** of a surviving test on the same code path.
- **Obsolete regressions** whose failure can no longer be expressed.
- **Game-content values** shard owners customize (era drop rates, loot and skill tables, single-creature tuning). Each customization would otherwise force a test fix.
## How it was decided
1. Every test was classified, with a reason, by a per-shard sweep over all 287 test files.
2. Each proposed deletion was then checked by a second, adversarial reviewer against the surviving tests and the production code.
3. Anything that was the only coverage of a separate code path was **kept**, even where it looked like a duplicate. Examples: the unsigned `SpanReader`/`SpanWriter` methods, the at-location versus bounds enumerators, null-map enumerables, the security filters, archive-journal state transitions. About 130 proposed deletions were rejected this way.
Whole files removed:
- `FishingTests`, apart from 3 tests: the map-edge scan, serpent cleanup, and SOS chest consumption. The SOS test now stops at the first chest instead of measuring a catch rate. The multi-million-cast rate simulations are gone.
- `LordOaksTests` and `MeerEnragedTests` (single-creature tests).
- `AutoArchiveHelperTests`, `JsonDiscoverableTypeAttributeTests`, `DecimalSerializationTests` and `EnumConversionTests` (tautologies, or tests of their own local helpers).
- `NetworkStatsTests`.
- `MigratedDataLoadTests` (a subset of `AllSpawnFilesLoadTests`).
- `SpawnerFixtureCapture`: a capture tool, not a test, and its `version == 12` assert can no longer pass. The `.bin` fixtures it produced stay.
## Tests
- Server.Tests: 811 pass.
- UOContent.Tests: 1,123 pass.
A follow-up PR, stacked on this one, fixes how the remaining tests behave: shared state, CI-vacuous tests, harness duplication.
> [!IMPORTANT]
> **Breaking Changes**
> - DecodePacket and EncodePacket delegates replaced with IClientEncryption interface
> - NetState.Connection (Socket) replaced with internal RingSocket management
> - NetState.RecvPipe and NetState.SendPipe removed (buffers managed internally)
## Summary
Upgrades the networking stack from PollGroup-based I/O to io_uring, significantly improving I/O performance on Linux.
This also adds native client encryption support for encrypted UO clients.
## Major Changes
io_uring Networking Architecture
- Replaced PollGroup with IORingGroup for async socket I/O operations
- Removed Pipe.cs (mirrored ring buffer) and TcpServer.cs in favor of RingSocketManager
- Added NetState.Network.cs - centralized network infrastructure handling accept, recv, send, and disconnect
completions
- Added SocketHelper.cs - platform-specific socket utilities for raw socket handle operations (getpeername,
getsockname)
- Buffer management now handled by RingSocketManager with configurable slab allocation
### Client Encryption Support
- Added full encryption stack in Network/Encryption/:
- EncryptionConfig.cs - configurable encryption modes (None, Unencrypted, Encrypted, Both)
- EncryptionManager.cs - encryption detection and initialization for login/game packets
- LoginEncryption.cs - handles login packet encryption with version-derived keys
- GameEncryption.cs - handles game server encryption using Twofish
- TwofishEngine.cs - optimized Twofish block cipher implementation
- LoginKeys.cs - encryption key table for client versions
- IClientEncryption.cs - interface for client encryption implementations
### NetState Improvements
- Replaced Socket Connection with RingSocket _socket for managed socket lifecycle
- Changed from GCHandle polling to event-based completion processing
- Disconnect handling now properly waits for pending sends to flush
- Simplified connecting socket management using lazy queue removal
### Configuration
- New settings: network.encryptionMode and network.encryptionDebug
- Encryption mode flags: Unencrypted, Encrypted, or Both
### Dependencies
- Replaced PollGroup NuGet package with IORingGroup
- Linux requires liburing-dev / liburing-devel package
### Test plan
- Verify server starts and accepts connections on Linux with io_uring
- Verify server starts and accepts connections on Windows (fallback to IOCP)
- Test unencrypted client connections (ClassicUO with encryption disabled)
- Test encrypted client connections if available
- Verify graceful disconnect flushes pending data
- Confirm CI builds pass on all target platforms
