diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..26bbfb0
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 3.10.0)
+project(test_plan_execute_t1)
+include(FetchContent)
+if (MSVC)
+    add_compile_options(/utf-8)
+endif()
+FetchContent_Declare(
+  googletest
+  URL https://github.com/google/googletest/archive/03597a01ee50ed33e9dfd640b249b4be3799d395.zip
+)
+# For Windows: Prevent overriding the parent project's compiler/linker settings
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+FetchContent_MakeAvailable(googletest)
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/../include)
+
+include(CTest)
+enable_testing()
+
+add_executable(test_plan_execute_t1 test_app.cpp ../src/app.cpp)
+
+target_link_libraries(test_plan_execute_t1 gtest gmock gtest_main)
+include(GoogleTest)
+gtest_discover_tests(test_plan_execute_t1)
\ No newline at end of file
diff --git a/tests/test_app.cpp b/tests/test_app.cpp
new file mode 100644
index 0000000..7c6eb8a
--- /dev/null
+++ b/tests/test_app.cpp
@@ -0,0 +1,102 @@
+#include <gtest/gtest.h>
+#include "app.hpp"
+#include <vector>
+#include <string>
+#include <chrono>
+
+// Mock classes to support testing if needed, or use direct access if public
+// Since CmsEngine is likely in a namespace or header, we assume app.hpp provides the interface
+
+class CmsEngineTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        engine_ = std::make_unique<CmsEngine>();
+    }
+
+    void TearDown() override {
+        engine_.reset();
+    }
+
+    std::unique_ptr<CmsEngine> engine_;
+};
+
+TEST_F(CmsEngineTest, TestPushNotification_Normal) {
+    NotificationMessage msg;
+    msg.id = "NOTIF-001";
+    msg.content = "Test notification";
+    msg.isRead = false;
+
+    EXPECT_NO_THROW(engine_->pushNotification(msg));
+    
+    auto unread = engine_->getUnreadNotifications();
+    EXPECT_EQ(unread.size(), 1);
+    EXPECT_EQ(unread[0].id, "NOTIF-001");
+}
+
+TEST_F(CmsEngineTest, TestGetUnreadNotifications_Empty) {
+    auto unread = engine_->getUnreadNotifications();
+    EXPECT_TRUE(unread.empty());
+}
+
+TEST_F(CmsEngineTest, TestGetUnreadNotifications_Mixed) {
+    NotificationMessage readMsg;
+    readMsg.id = "READ-001";
+    readMsg.content = "Read message";
+    readMsg.isRead = true;
+
+    NotificationMessage unreadMsg;
+    unreadMsg.id = "UNREAD-001";
+    unreadMsg.content = "Unread message";
+    unreadMsg.isRead = false;
+
+    engine_->pushNotification(readMsg);
+    engine_->pushNotification(unreadMsg);
+
+    auto unread = engine_->getUnreadNotifications();
+    EXPECT_EQ(unread.size(), 1);
+    EXPECT_EQ(unread[0].id, "UNREAD-001");
+}
+
+TEST_F(CmsEngineTest, TestSwitchMode_Success) {
+    EXPECT_TRUE(engine_->switchMode(RunMode::AutoExec));
+    
+    auto context = engine_->getSystemContext();
+    EXPECT_EQ(context.currentMode, RunMode::AutoExec);
+}
+
+TEST_F(CmsEngineTest, TestSwitchMode_DegradedRestriction) {
+    engine_->switchMode(RunMode::Degraded);
+    
+    // Should fail to switch out of degraded mode
+    EXPECT_FALSE(engine_->switchMode(RunMode::Idle));
+    
+    auto context = engine_->getSystemContext();
+    EXPECT_EQ(context.currentMode, RunMode::Degraded);
+}
+
+TEST_F(CmsEngineTest, TestGetSystemContext_Valid) {
+    engine_->switchMode(RunMode::HumanLoop);
+    
+    auto context = engine_->getSystemContext();
+    EXPECT_EQ(context.currentMode, RunMode::HumanLoop);
+    EXPECT_NE(context.switchTime.time_since_epoch(), std::chrono::seconds(0));
+}
+
+TEST_F(CmsEngineTest, TestGetSummary_Format) {
+    engine_->switchMode(RunMode::AutoExec);
+    
+    std::string summary = engine_->getSummary();
+    
+    EXPECT_NE(summary.find("Events"), std::string::npos);
+    EXPECT_NE(summary.find("Plans"), std::string::npos);
+    EXPECT_NE(summary.find("Templates"), std::string::npos);
+    EXPECT_NE(summary.find("Monitor Nodes"), std::string::npos);
+    EXPECT_NE(summary.find("Active Sessions"), std::string::npos);
+    EXPECT_NE(summary.find("Notifications"), std::string::npos);
+    EXPECT_NE(summary.find("AutoExec"), std::string::npos);
+}
+
+int main(int argc, char **argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}
\ No newline at end of file