test: Add RHI integration tests and update unit tests

- Add CommandQueue unit tests for WaitForIdle and synchronization
- Add SwapChain unit tests for Present and buffer operations
- Add Texture unit tests for various texture types and mipmaps
- Fix RHIIntegrationFixture with proper logging and debug output
- Update minimal integration test with RHI abstraction layer
- Add GT reference image for minimal test
- Update TEST_SPEC.md documentation

tests/RHI/integration/fixtures/RHIIntegrationFixture.h

@@ -12,11 +12,23 @@
 #include "XCEngine/RHI/RHIScreenshot.h"
 #include "XCEngine/RHI/RHIEnums.h"
 #include "XCEngine/RHI/OpenGL/OpenGLDevice.h"
+#include "XCEngine/Debug/Logger.h"
+#include "XCEngine/Debug/ConsoleLogSink.h"
+
+#if defined(XCENGINE_SUPPORT_D3D12)
+#include "XCEngine/RHI/D3D12/D3D12Device.h"
+#include "XCEngine/RHI/D3D12/D3D12CommandList.h"
+#include "XCEngine/RHI/D3D12/D3D12SwapChain.h"
+#include "XCEngine/RHI/D3D12/D3D12Texture.h"
+#include "XCEngine/RHI/D3D12/D3D12DescriptorHeap.h"
+#endif
 
 namespace XCEngine {
 namespace RHI {
 namespace Integration {
 
+void Log(const char* format, ...);
+
 class RHIIntegrationFixture : public ::testing::TestWithParam<RHIType> {
 protected:
     void SetUp() override;
@@ -34,6 +46,8 @@ protected:
     RHIType GetBackendType() const { return GetParam(); }
     HWND GetWindowHandle() const { return mWindow; }
     int GetCurrentBackBufferIndex() const { return mCurrentBackBufferIndex; }
+    RHITexture* GetCurrentBackBuffer() { return mSwapChain ? mSwapChain->GetCurrentBackBuffer() : nullptr; }
+    void SetRenderTargetForClear();
 
     virtual void RenderFrame() {}
 
@@ -48,6 +62,13 @@ private:
     RHIScreenshot* mScreenshot = nullptr;
     HWND mWindow = nullptr;
     int mCurrentBackBufferIndex = 0;
+
+#if defined(XCENGINE_SUPPORT_D3D12)
+    D3D12DescriptorHeap* mRTVHeap = nullptr;
+    D3D12DescriptorHeap* mDSVHeap = nullptr;
+    std::vector<RHIResourceView*> mRTVs;
+    RHIResourceView* mDSV = nullptr;
+#endif
 };
 
 } // namespace Integration