Add deterministic integration scenarios booting real subsystems (ECS / Physics / Render / Network / Scene)

[Krilliac]

Motivation

• Provide focused integration tests that boot real engine subsystems (not mocks) to validate cross-system contracts and deterministic behaviour for physics/ECS, rendering constant-buffer updates, networking prediction/reconciliation under latency/jitter, and scene snapshot roundtrips.

Description

• Added a new integration test suite Tests/Integration/TestSubsystemIntegrationScenarios.cpp that uses a diagnostics-style harness to initialize EngineContext, PhysicsSystem, event bus, and other subsystems and contains four focused scenarios for ECS+Physics, ECS+Rendering, Networking+ECS, and Scene save/load roundtrip with identity checks.
• Implemented small, test-local helpers in the new file: world-matrix/constant-buffer diff updater, replication packet (de)serializer, and deterministic ComponentSerializerEntry registrations for transform/name to ensure snapshot identity round-trips.
• Wired the new test into the test runner by updating Tests/CMakeLists.txt to include Integration/TestSubsystemIntegrationScenarios.cpp in the SparkTests target.
• Used existing engine subsystems/APIs in tests: PhysicsUpdateSystem, PhysicsBody readback, Spark::Graphics::ConstantBufferDiffManager, Spark::Net::InstabilitySimulator, ClientPrediction, and Spark::Editor::SceneSnapshotSerializer with the ComponentSerializerRegistry.

Testing

• Ran clang-format -i Tests/Integration/TestSubsystemIntegrationScenarios.cpp successfully to match project formatting rules.
• Ran cmake --preset linux-gcc-release which configured successfully for the Linux-GCC release preset (tests enabled) without errors.
• Per-file syntax validation with g++ -std=gnu++23 -fsyntax-only including the engine include paths and entt stub passed for the new source file.
• Kicked off cmake --build ... --target SparkTests which began building the test target and made substantive progress in this environment, but the full compilation of the entire SparkTests target is long-running and did not complete within the interactive session timeout (partial build progress observed).

---

Codex Task

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.

[github-actions]

✅ CI Errors Resolved

All previously reported errors have been fixed. All builds passing.

Last checked: 2026-04-09T05:40:01Z

[github-actions]

Code Coverage (GCC + lcov)

Utils/MemoryMonitor.cpp                        | 9.3%   236| 0.0%  19|    -    0
Utils/MemoryMonitor.h                          |85.7%    14| 0.0%  12|    -    0
Utils/MultiISA.h                               |42.9%    14| 0.0%   6|    -    0
Utils/NetworkHealthMonitor.cpp                 | 113%    15| 0.0%   2|    -    0
Utils/NetworkHealthMonitor.h                   |    -     0|    -   0|    -    0
Utils/OpaqueHandle.h                           | 282%    11| 0.0%  15|    -    0
Utils/ProcessLinux.cpp                         |16.5%   182| 0.0%  28|    -    0
Utils/Profiler.cpp                             |14.2%   113| 0.0%  15|    -    0
Utils/Profiler.h                               |36.4%    33| 0.0%  12|    -    0
Utils/RandomEngine.h                           |29.3%    41| 0.0%  12|    -    0
Utils/Result.h                                 | 100%    29| 0.0%  28|    -    0
Utils/RingBuffer.h                             | 108%    59| 0.0%  64|    -    0
Utils/ScopeGuard.h                             | 142%    36| 0.0%  51|    -    0
Utils/ScopedTimer.h                            |25.0%    12| 0.0%   3|    -    0
Utils/Serializer.h                             | 100%    48| 0.0%  42|    -    0
Utils/SparkConsole.cpp                         |28.5%   144| 0.0%  17|    -    0
Utils/SparkConsole.h                           | 100%     2| 0.0%   2|    -    0
Utils/SparkError.h                             |10.9%    55| 0.0%   6|    -    0
Utils/SplinePath.h                             |    -     0|    -   0|    -    0
Utils/StackTrace.h                             |10.8%    74| 0.0%   8|    -    0
Utils/StateMachine.h                           |54.0%    63| 0.0%  32|    -    0
Utils/StringUtils.h                            |18.1%   116| 0.0%  21|    -    0
Utils/Telemetry.h                              |21.8%    87| 0.0%  16|    -    0
Utils/ThreadDebugger.h                         |11.6%   199| 0.0%  23|    -    0
Utils/ThreadSafeQueue.h                        |27.5%    40| 0.0%  11|    -    0
Utils/TimerManager.h                           |19.8%    96| 0.0%  19|    -    0
Utils/UUID.h                                   |43.2%    37| 0.0%  16|    -    0
Utils/Validate.h                               |    -     0|    -   0|    -    0

[/home/runner/work/SparkEngine/SparkEngine/SparkSDK/Include/Spark/]
IEngineContext.h                               |6700%     1| 0.0%   1|    -    0
Version.h                                      |    -     0|    -   0|    -    0
================================================================================
                                         Total:|29.2% 23463| 0.0%  4k|    -    0

Per-Subsystem Coverage

Subsystem	Lines	Hit	Coverage	Threshold	Status
AI	2776	694	25%	35%	❌
Animation	160	154	96.2%	35%	✅
Audio	0	0	0%	30%	✅
Camera	0	0	0%	40%	✅
Core	2184	1387	63.5%	40%	✅
ECS	190	114	60%	40%	✅
Editor	5997	1864	31.1%	25%	✅
GameModules	6244	3131	50.1%	30%	✅
Graphics	7172	3770	52.6%	30%	✅
Networking	3322	2145	64.6%	35%	✅
Physics	0	0	0%	35%	✅
Scripting	0	0	0%	30%	✅
Utils	7625	4812	63.1%	60%	✅

Total: 50.7% (18071/35670 lines)