Add Phase 5: SwapChain tests (3 tests)

- Add SwapChain tests: Initialize, Present, Resize

=== OpenGL Test Suite Complete ===
Total: 49 tests across all phases:
- Phase 1: Device, Buffer, Fence (17 tests)
- Phase 2: Texture, Sampler (9 tests)
- Phase 3: Shader, PipelineState, VertexArray (11 tests)
- Phase 4: CommandList, RTV, DSV (9 tests)
- Phase 5: SwapChain (3 tests)

tests/RHI/OpenGL/CMakeLists.txt

@@ -31,6 +31,7 @@ set(TEST_SOURCES
     test_command_list.cpp
     test_render_target_view.cpp
     test_depth_stencil_view.cpp
+    test_swap_chain.cpp
 )
 
 add_executable(opengl_engine_tests ${TEST_SOURCES})

tests/RHI/OpenGL/test_swap_chain.cpp

@@ -0,0 +1,41 @@
+#include "fixtures/OpenGLTestFixture.h"
+#include "XCEngine/RHI/OpenGL/OpenGLSwapChain.h"
+
+using namespace XCEngine::RHI;
+
+TEST_F(OpenGLTestFixture, SwapChain_Initialize_Window) {
+    OpenGLSwapChain swapChain;
+    GLFWwindow* window = GetWindow();
+    
+    bool result = swapChain.Initialize(window, 800, 600);
+    
+    ASSERT_TRUE(result);
+    
+    swapChain.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, SwapChain_Present) {
+    OpenGLSwapChain swapChain;
+    GLFWwindow* window = GetWindow();
+    swapChain.Initialize(window, 800, 600);
+    
+    swapChain.Present();
+    
+    GLenum error = glGetError();
+    EXPECT_EQ(error, GL_NO_ERROR);
+    
+    swapChain.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, SwapChain_Resize_ChangesSize) {
+    OpenGLSwapChain swapChain;
+    GLFWwindow* window = GetWindow();
+    swapChain.Initialize(window, 800, 600);
+    
+    swapChain.Resize(1024, 768);
+    
+    EXPECT_EQ(swapChain.GetWidth(), 1024);
+    EXPECT_EQ(swapChain.GetHeight(), 768);
+    
+    swapChain.Shutdown();
+}