diff --git a/tests/RHI/OpenGL/CMakeLists.txt b/tests/RHI/OpenGL/CMakeLists.txt
index 4d95cf7e..1bc7ad0d 100644
--- a/tests/RHI/OpenGL/CMakeLists.txt
+++ b/tests/RHI/OpenGL/CMakeLists.txt
@@ -25,6 +25,9 @@ set(TEST_SOURCES
     test_fence.cpp
     test_texture.cpp
     test_sampler.cpp
+    test_shader.cpp
+    test_pipeline_state.cpp
+    test_vertex_array.cpp
 )
 
 add_executable(opengl_engine_tests ${TEST_SOURCES})
diff --git a/tests/RHI/OpenGL/test_pipeline_state.cpp b/tests/RHI/OpenGL/test_pipeline_state.cpp
new file mode 100644
index 00000000..c9289a4a
--- /dev/null
+++ b/tests/RHI/OpenGL/test_pipeline_state.cpp
@@ -0,0 +1,68 @@
+#include "fixtures/OpenGLTestFixture.h"
+#include "XCEngine/RHI/OpenGL/OpenGLPipelineState.h"
+
+using namespace XCEngine::RHI;
+
+TEST_F(OpenGLTestFixture, PipelineState_SetDepthStencilState) {
+    OpenGLPipelineState pipeline;
+    
+    DepthStencilState state;
+    state.depthTestEnable = true;
+    state.depthWriteEnable = true;
+    state.depthFunc = ComparisonFunc::Less;
+    
+    pipeline.SetDepthStencilState(state);
+    pipeline.ApplyDepthStencil();
+    
+    GLint depthTest = 0;
+    glGetIntegerv(GL_DEPTH_TEST, &depthTest);
+    EXPECT_EQ(depthTest, 1);
+    
+    GLint depthMask = 0;
+    glGetIntegerv(GL_DEPTH_WRITEMASK, &depthMask);
+    EXPECT_EQ(depthMask, 1);
+}
+
+TEST_F(OpenGLTestFixture, PipelineState_SetBlendState) {
+    OpenGLPipelineState pipeline;
+    
+    BlendState state;
+    state.blendEnable = true;
+    state.srcBlend = BlendFactor::SrcAlpha;
+    state.dstBlend = BlendFactor::OneMinusSrcAlpha;
+    
+    pipeline.SetBlendState(state);
+    pipeline.ApplyBlend();
+    
+    GLint blend = 0;
+    glGetIntegerv(GL_BLEND, &blend);
+    EXPECT_EQ(blend, 1);
+}
+
+TEST_F(OpenGLTestFixture, PipelineState_SetViewport_SetScissor) {
+    OpenGLPipelineState pipeline;
+    
+    ViewportState viewport;
+    viewport.x = 0;
+    viewport.y = 0;
+    viewport.width = 800;
+    viewport.height = 600;
+    
+    ScissorState scissor;
+    scissor.enable = true;
+    scissor.x = 0;
+    scissor.y = 0;
+    scissor.width = 800;
+    scissor.height = 600;
+    
+    pipeline.SetViewport(viewport);
+    pipeline.SetScissor(scissor);
+    pipeline.ApplyViewport();
+    
+    GLint viewportArr[4] = {};
+    glGetIntegerv(GL_VIEWPORT, viewportArr);
+    EXPECT_EQ(viewportArr[0], 0);
+    EXPECT_EQ(viewportArr[1], 0);
+    EXPECT_EQ(viewportArr[2], 800);
+    EXPECT_EQ(viewportArr[3], 600);
+}
diff --git a/tests/RHI/OpenGL/test_shader.cpp b/tests/RHI/OpenGL/test_shader.cpp
new file mode 100644
index 00000000..d76ffb10
--- /dev/null
+++ b/tests/RHI/OpenGL/test_shader.cpp
@@ -0,0 +1,119 @@
+#include "fixtures/OpenGLTestFixture.h"
+#include "XCEngine/RHI/OpenGL/OpenGLShader.h"
+
+using namespace XCEngine::RHI;
+
+TEST_F(OpenGLTestFixture, Shader_Compile_VertexFragment) {
+    const char* vertexSource = R"(
+        #version 330 core
+        in vec3 aPosition;
+        void main() {
+            gl_Position = vec4(aPosition, 1.0);
+        }
+    )";
+    
+    const char* fragmentSource = R"(
+        #version 330 core
+        out vec4 FragColor;
+        void main() {
+            FragColor = vec4(1.0, 0.0, 0.0, 1.0);
+        }
+    )";
+    
+    OpenGLShader shader;
+    bool result = shader.Compile(vertexSource, fragmentSource);
+    
+    ASSERT_TRUE(result);
+    EXPECT_TRUE(shader.IsValid());
+    EXPECT_NE(shader.GetID(), 0u);
+    
+    shader.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, Shader_Compile_WithGeometry) {
+    const char* vertexSource = R"(
+        #version 330 core
+        void main() {
+            gl_Position = vec4(0.0);
+        }
+    )";
+    
+    const char* fragmentSource = R"(
+        #version 330 core
+        void main() {
+        }
+    )";
+    
+    const char* geometrySource = R"(
+        #version 330 core
+        layout(triangles) in;
+        layout(triangle_strip, max_vertices = 3) out;
+        void main() {
+            for(int i = 0; i < 3; i++) {
+                gl_Position = gl_in[i].gl_Position;
+                EmitVertex();
+            }
+            EndPrimitive();
+        }
+    )";
+    
+    OpenGLShader shader;
+    bool result = shader.Compile(vertexSource, fragmentSource, geometrySource);
+    
+    ASSERT_TRUE(result);
+    EXPECT_TRUE(shader.IsValid());
+    
+    shader.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, Shader_Compile_InvalidSource) {
+    const char* invalidSource = R"(
+        #version 330 core
+        void main() {
+            undefined_symbol;
+        }
+    )";
+    
+    OpenGLShader shader;
+    bool result = shader.Compile(invalidSource, "void main() { }");
+    
+    EXPECT_FALSE(result);
+    EXPECT_FALSE(shader.IsValid());
+    
+    shader.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, Shader_SetUniforms) {
+    const char* vs = R"(
+        #version 330 core
+        void main() { gl_Position = vec4(0.0); }
+    )";
+    const char* fs = R"(
+        #version 330 core
+        uniform int uIntValue;
+        uniform float uFloatValue;
+        uniform vec3 uVec3Value;
+        uniform mat4 uMat4Value;
+        out vec4 FragColor;
+        void main() { FragColor = vec4(1.0); }
+    )";
+    
+    OpenGLShader shader;
+    shader.Compile(vs, fs);
+    ASSERT_TRUE(shader.IsValid());
+    
+    shader.Use();
+    
+    shader.SetInt("uIntValue", 42);
+    shader.SetFloat("uFloatValue", 3.14f);
+    shader.SetVec3("uVec3Value", 1.0f, 2.0f, 3.0f);
+    
+    float mat[16] = {};
+    mat[0] = 1.0f; mat[5] = 1.0f; mat[10] = 1.0f; mat[15] = 1.0f;
+    shader.SetMat4("uMat4Value", mat);
+    
+    GLenum error = glGetError();
+    EXPECT_EQ(error, GL_NO_ERROR);
+    
+    shader.Shutdown();
+}
diff --git a/tests/RHI/OpenGL/test_vertex_array.cpp b/tests/RHI/OpenGL/test_vertex_array.cpp
new file mode 100644
index 00000000..93bd048e
--- /dev/null
+++ b/tests/RHI/OpenGL/test_vertex_array.cpp
@@ -0,0 +1,70 @@
+#include "fixtures/OpenGLTestFixture.h"
+#include "XCEngine/RHI/OpenGL/OpenGLVertexArray.h"
+#include "XCEngine/RHI/OpenGL/OpenGLBuffer.h"
+
+using namespace XCEngine::RHI;
+
+TEST_F(OpenGLTestFixture, VertexArray_Initialize_CreatesVAO) {
+    OpenGLVertexArray vao;
+    
+    bool result = vao.Initialize();
+    
+    ASSERT_TRUE(result);
+    EXPECT_NE(vao.GetID(), 0u);
+    
+    vao.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, VertexArray_AddVertexBuffer) {
+    OpenGLVertexArray vao;
+    vao.Initialize();
+    
+    OpenGLBuffer buffer;
+    buffer.InitializeVertexBuffer(nullptr, 64);
+    
+    VertexAttribute attr;
+    attr.index = 0;
+    attr.count = 3;
+    attr.type = GL_FLOAT;
+    attr.normalized = false;
+    attr.stride = sizeof(float) * 3;
+    attr.offset = 0;
+    
+    vao.AddVertexBuffer(buffer.GetID(), attr);
+    
+    EXPECT_EQ(vao.GetID(), 1u);
+    
+    buffer.Shutdown();
+    vao.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, VertexArray_SetIndexBuffer) {
+    OpenGLVertexArray vao;
+    vao.Initialize();
+    
+    OpenGLBuffer buffer;
+    buffer.InitializeIndexBuffer(nullptr, 12);
+    
+    vao.SetIndexBuffer(buffer.GetID(), GL_UNSIGNED_INT);
+    
+    EXPECT_NE(vao.GetIndexBuffer(), 0u);
+    
+    buffer.Shutdown();
+    vao.Shutdown();
+}
+
+TEST_F(OpenGLTestFixture, VertexArray_Bind_Unbind) {
+    OpenGLVertexArray vao;
+    vao.Initialize();
+    
+    vao.Bind();
+    GLint boundVAO = 0;
+    glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &boundVAO);
+    EXPECT_EQ(boundVAO, static_cast<GLint>(vao.GetID()));
+    
+    vao.Unbind();
+    glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &boundVAO);
+    EXPECT_EQ(boundVAO, 0);
+    
+    vao.Shutdown();
+}