diff --git a/tests/test_alert_manager.cpp b/tests/test_alert_manager.cpp
index 5bc247a..5e574a7 100644
--- a/tests/test_alert_manager.cpp
+++ b/tests/test_alert_manager.cpp
@@ -3,265 +3,142 @@
 #include <vector>
 #include <string>
 
-// Mock for time to ensure deterministic tests
-static uint32_t mock_timestamp = 1640995200; // 2022-01-01 00:00:00 UTC
+// Mock time function for deterministic testing
+uint32_t mock_timestamp = 1640995200; // Fixed timestamp for testing
 
-class MockTime { 
-public:
-    static uint32_t getTimestamp() { return mock_timestamp; }
-    static void setTimestamp(uint32_t t) { mock_timestamp = t; }
-};
-
-// Helper function to compare AlertInfo
-bool operator==(const AlertInfo& a, const AlertInfo& b) {
-    return a.type == b.type &&
-           a.status == b.status &&
-           a.trigger_time == b.trigger_time &&
-           a.acknowledge_time == b.acknowledge_time &&
-           a.resolve_time == b.resolve_time &&
-           a.description == b.description;
+// Override the time function to return a fixed value
+uint32_t get_mock_time() {
+    return mock_timestamp;
 }
 
-// Test fixture
+// Replace the real time function with mock
+extern "C" uint32_t std_time(nullptr) {
+    return get_mock_time();
+}
+
+// Test fixture for AlertManager
 class AlertManagerTest : public ::testing::Test {
 protected:
-    AlertManager manager;
+    AlertManager alert_manager;
 
     void SetUp() override {
         mock_timestamp = 1640995200;
-        manager.initialize();
+        alert_manager.initialize();
     }
 
     void TearDown() override {
-        manager.clearHistory();
+        alert_manager.resetAllAlerts();
     }
 };
 
-TEST_F(AlertManagerTest, testAlertManagerDefaultInitialization) {
-    EXPECT_FLOAT_EQ(manager.getAltitudeThresholds().first, 100.0f);
-    EXPECT_FLOAT_EQ(manager.getAltitudeThresholds().second, -50.0f);
-    EXPECT_TRUE(manager.getActiveAlerts().empty());
-    EXPECT_TRUE(manager.getAlertHistory(10).empty());
+// Test case: 正常输入测试 - 设置合法阈值
+TEST_F(AlertManagerTest, testSetAltitudeThresholdsNormalInput) {
+    const float upper = 200.0f;
+    const float lower = 50.0f;
+
+    alert_manager.setAltitudeThresholds(upper, lower);
+
+    EXPECT_FLOAT_EQ(alert_manager.getUpperThreshold(), upper);
+    EXPECT_FLOAT_EQ(alert_manager.getLowerThreshold(), lower);
+
+    // Verify that active alerts are reset
+    auto active_alerts = alert_manager.getActiveAlerts();
+    EXPECT_TRUE(active_alerts.empty());
 }
 
-TEST_F(AlertManagerTest, testInitialize) {
-    // No direct output assertion, but verify initialization logic
-    // This is tested implicitly via constructor
-    EXPECT_NO_FATAL_FAILURE(manager.initialize());
+// Test case: 边界值测试 - 上限等于下限（非法输入）
+TEST_F(AlertManagerTest, testSetAltitudeThresholdsBoundaryEqual) {
+    const float upper = 100.0f;
+    const float lower = 100.0f;
+
+    // Capture stderr output
+    testing::internal::CaptureStderr();
+    alert_manager.setAltitudeThresholds(upper, lower);
+    std::string stderr_output = testing::internal::GetCapturedStderr();
+
+    EXPECT_NE(stderr_output.find("错误：上限阈值必须大于下限阈值。"), std::string::npos);
+    EXPECT_FLOAT_EQ(alert_manager.getUpperThreshold(), 100.0f); // Should remain unchanged
+    EXPECT_FLOAT_EQ(alert_manager.getLowerThreshold(), -50.0f); // Default value
 }
 
-TEST_F(AlertManagerTest, testCheckAltitudeAlertNormal) {
-    mock_timestamp = 1640995200;
-    manager.checkAltitudeAlert(105.0f, mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].type, AlertType::ALTITUDE_UPPER);
-    EXPECT_EQ(alerts[0].status, AlertStatus::ACTIVE);
-    EXPECT_EQ(alerts[0].trigger_time, mock_timestamp);
+// Test case: 异常输入测试 - 上限小于下限
+TEST_F(AlertManagerTest, testSetAltitudeThresholdsInvalidInput) {
+    const float upper = 50.0f;
+    const float lower = 100.0f;
+
+    // Capture stderr output
+    testing::internal::CaptureStderr();
+    alert_manager.setAltitudeThresholds(upper, lower);
+    std::string stderr_output = testing::internal::GetCapturedStderr();
+
+    EXPECT_NE(stderr_output.find("错误：上限阈值必须大于下限阈值。"), std::string::npos);
+    EXPECT_FLOAT_EQ(alert_manager.getUpperThreshold(), 100.0f); // Should remain unchanged
+    EXPECT_FLOAT_EQ(alert_manager.getLowerThreshold(), -50.0f); // Default value
 }
 
-TEST_F(AlertManagerTest, testCheckAltitudeAlertBelowLower) {
-    mock_timestamp = 1640995200;
-    manager.checkAltitudeAlert(-55.0f, mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].type, AlertType::ALTITUDE_LOWER);
-    EXPECT_EQ(alerts[0].status, AlertStatus::ACTIVE);
+// Test case: 特殊场景测试 - 阈值更新后重置预警状态
+TEST_F(AlertManagerTest, testSetAltitudeThresholdsResetAlerts) {
+    // Trigger an altitude upper alert
+    alert_manager.checkAltitudeAlert(150.0f, mock_timestamp);
+    auto active_alerts = alert_manager.getActiveAlerts();
+    EXPECT_EQ(active_alerts.size(), 1);
+    EXPECT_EQ(active_alerts[0].type, AlertType::ALTITUDE_UPPER);
+
+    // Update thresholds
+    alert_manager.setAltitudeThresholds(180.0f, 50.0f);
+
+    // Check if alert was reset
+    active_alerts = alert_manager.getActiveAlerts();
+    EXPECT_TRUE(active_alerts.empty());
 }
 
-TEST_F(AlertManagerTest, testCheckAltitudeAlertResetWhenNormal) {
-    mock_timestamp = 1640995200;
-    manager.checkAltitudeAlert(105.0f, mock_timestamp); // Trigger upper
-    mock_timestamp = 1640995201;
-    manager.checkAltitudeAlert(90.0f, mock_timestamp); // Reset
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
+// Test case: 正常输入测试 - 获取活动预警信息
+TEST_F(AlertManagerTest, testGetActiveAlertsNormal) {
+    // Add a simulated active alert
+    AlertInfo alert;
+    alert.type = AlertType::ALTITUDE_UPPER;
+    alert.status = AlertStatus::ACTIVE;
+    alert.trigger_time = mock_timestamp;
+    alert.description = "High altitude";
+
+    alert_manager.alerts_[AlertType::ALTITUDE_UPPER] = alert;
+
+    auto result = alert_manager.getActiveAlerts();
+
+    EXPECT_EQ(result.size(), 1);
+    EXPECT_EQ(result[0].type, AlertType::ALTITUDE_UPPER);
+    EXPECT_EQ(result[0].status, AlertStatus::ACTIVE);
+    EXPECT_EQ(result[0].trigger_time, mock_timestamp);
+    EXPECT_EQ(result[0].description, "High altitude");
 }
 
-TEST_F(AlertManagerTest, testSetAltitudeThresholdsValid) {
-    manager.setAltitudeThresholds(200.0f, -100.0f);
-    auto thresholds = manager.getAltitudeThresholds();
-    EXPECT_FLOAT_EQ(thresholds.first, 200.0f);
-    EXPECT_FLOAT_EQ(thresholds.second, -100.0f);
+// Test case: 边界值测试 - 无活动预警时获取结果为空
+TEST_F(AlertManagerTest, testGetActiveAlertsEmpty) {
+    auto result = alert_manager.getActiveAlerts();
+
+    EXPECT_TRUE(result.empty());
 }
 
-TEST_F(AlertManagerTest, testSetAltitudeThresholdsInvalid) {
-    EXPECT_NO_FATAL_FAILURE(manager.setAltitudeThresholds(50.0f, 100.0f));
-    // Should print error, but no crash
-    EXPECT_FLOAT_EQ(manager.getAltitudeThresholds().first, 100.0f);
-    EXPECT_FLOAT_EQ(manager.getAltitudeThresholds().second, -50.0f);
-}
+// Test case: 特殊场景测试 - 多个活动预警同时存在
+TEST_F(AlertManagerTest, testGetActiveAlertsMultipleAlerts) {
+    // Simulate two active alerts
+    AlertInfo upper_alert, lower_alert;
+    upper_alert.type = AlertType::ALTITUDE_UPPER;
+    upper_alert.status = AlertStatus::ACTIVE;
+    upper_alert.trigger_time = mock_timestamp;
+    upper_alert.description = "Above upper limit";
 
-TEST_F(AlertManagerTest, testTriggerSensorFailure) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].type, AlertType::SENSOR_FAILURE);
-    EXPECT_EQ(alerts[0].status, AlertStatus::ACTIVE);
-    EXPECT_EQ(alerts[0].trigger_time, mock_timestamp);
-}
+    lower_alert.type = AlertType::ALTITUDE_LOWER;
+    lower_alert.status = AlertStatus::ACTIVE;
+    lower_alert.trigger_time = mock_timestamp + 1;
+    lower_alert.description = "Below lower limit";
 
-TEST_F(AlertManagerTest, testTriggerLowBattery) {
-    mock_timestamp = 1640995200;
-    manager.triggerLowBattery(mock_timestamp, 15.0f);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].type, AlertType::LOW_BATTERY);
-    EXPECT_EQ(alerts[0].status, AlertStatus::ACTIVE);
-    EXPECT_NE(alerts[0].description.find("15.0%"), std::string::npos);
-}
+    alert_manager.alerts_[AlertType::ALTITUDE_UPPER] = upper_alert;
+    alert_manager.alerts_[AlertType::ALTITUDE_LOWER] = lower_alert;
 
-TEST_F(AlertManagerTest, testTriggerCommunicationError) {
-    mock_timestamp = 1640995200;
-    manager.triggerCommunicationError(mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].type, AlertType::COMMUNICATION_ERROR);
-    EXPECT_EQ(alerts[0].status, AlertStatus::ACTIVE);
-}
+    auto result = alert_manager.getActiveAlerts();
 
-TEST_F(AlertManagerTest, testAcknowledgeAllAlerts) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
-    mock_timestamp = 1640995202;
-    manager.acknowledgeAllAlerts(mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
-    EXPECT_EQ(alerts.size(), 0);
+    EXPECT_EQ(result.size(), 2);
+    EXPECT_EQ(result[0].type, AlertType::ALTITUDE_UPPER);
+    EXPECT_EQ(result[1].type, AlertType::ALTITUDE_LOWER);
 }
-
-TEST_F(AlertManagerTest, testAcknowledgeAlert) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    mock_timestamp = 1640995201;
-    manager.acknowledgeAlert(AlertType::SENSOR_FAILURE, mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
-}
-
-TEST_F(AlertManagerTest, testResetAlert) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    manager.resetAlert(AlertType::SENSOR_FAILURE);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
-}
-
-TEST_F(AlertManagerTest, testResetAllAlerts) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
-    manager.resetAllAlerts();
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
-}
-
-TEST_F(AlertManagerTest, testHasActiveAlerts) {
-    EXPECT_FALSE(manager.hasActiveAlerts());
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    EXPECT_TRUE(manager.hasActiveAlerts());
-}
-
-TEST_F(AlertManagerTest, testHasUnacknowledgedAlerts) {
-    EXPECT_FALSE(manager.hasUnacknowledgedAlerts());
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    EXPECT_TRUE(manager.hasUnacknowledgedAlerts());
-    manager.acknowledgeAllAlerts(mock_timestamp + 1);
-    EXPECT_FALSE(manager.hasUnacknowledgedAlerts());
-}
-
-TEST_F(AlertManagerTest, testGetActiveAlerts) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].type, AlertType::SENSOR_FAILURE);
-}
-
-TEST_F(AlertManagerTest, testGetAlertHistoryMaxCount) {
-    mock_timestamp = 1640995200;
-    for (int i = 0; i < 15; ++i) {
-        manager.triggerSensorFailure(mock_timestamp + i);
-    }
-    auto history = manager.getAlertHistory(10);
-    EXPECT_EQ(history.size(), 10);
-}
-
-TEST_F(AlertManagerTest, testGetStatusDescriptionNoAlerts) {
-    std::string desc = manager.getStatusDescription();
-    EXPECT_EQ(desc, "系统状态：正常");
-}
-
-TEST_F(AlertManagerTest, testGetStatusDescriptionWithAlerts) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    std::string desc = manager.getStatusDescription();
-    EXPECT_NE(desc.find("有1个活动预警"), std::string::npos);
-    EXPECT_NE(desc.find("传感器故障"), std::string::npos);
-}
-
-TEST_F(AlertManagerTest, testClearHistory) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    manager.clearHistory();
-    EXPECT_TRUE(manager.getAlertHistory(10).empty());
-}
-
-TEST_F(AlertManagerTest, testAddToHistoryLimit) {
-    mock_timestamp = 1640995200;
-    for (int i = 0; i < 100; ++i) {
-        manager.triggerSensorFailure(mock_timestamp + i);
-    }
-    auto history = manager.getAlertHistory(10);
-    EXPECT_EQ(history.size(), 10);
-}
-
-TEST_F(AlertManagerTest, testTriggerAlert) {
-    mock_timestamp = 1640995200;
-    manager.triggerAlert(AlertType::SENSOR_FAILURE, mock_timestamp, "Test alert");
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_EQ(alerts.size(), 1);
-    EXPECT_EQ(alerts[0].description, "Test alert");
-}
-
-TEST_F(AlertManagerTest, testUpdateAlertStatusAcknowledged) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    mock_timestamp = 1640995201;
-    manager.updateAlertStatus(AlertType::SENSOR_FAILURE, AlertStatus::ACKNOWLEDGED, mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
-}
-
-TEST_F(AlertManagerTest, testUpdateAlertStatusResolved) {
-    mock_timestamp = 1640995200;
-    manager.triggerSensorFailure(mock_timestamp);
-    mock_timestamp = 1640995201;
-    manager.updateAlertStatus(AlertType::SENSOR_FAILURE, AlertStatus::RESOLVED, mock_timestamp);
-    auto alerts = manager.getActiveAlerts();
-    EXPECT_TRUE(alerts.empty());
-}
-
-TEST_F(AlertManagerTest, testGetAlertTypeName) {
-    EXPECT_EQ(manager.getAlertTypeName(AlertType::ALTITUDE_UPPER), "高度上限预警");
-    EXPECT_EQ(manager.getAlertTypeName(AlertType::NONE), "无");
-    EXPECT_EQ(manager.getAlertTypeName(static_cast<AlertType>(99)), "未知预警");
-}
-
-TEST_F(AlertManagerTest, testGetAlertStatusName) {
-    EXPECT_EQ(manager.getAlertStatusName(AlertStatus::ACTIVE), "预警中");
-    EXPECT_EQ(manager.getAlertStatusName(AlertStatus::INACTIVE), "未激活");
-    EXPECT_EQ(manager.getAlertStatusName(static_cast<AlertStatus>(99)), "未知状态");
-}
-
-TEST_F(AlertManagerTest, testDestructorDoesNotCrash) {
-    // Verify destructor doesn't throw or crash
-    EXPECT_NO_FATAL_FAILURE({
-        AlertManager* mgr = new AlertManager();
-        delete mgr;
-    });
-}
\ No newline at end of file