diff --git a/services/EmailNotificationService.java b/services/EmailNotificationService.java
new file mode 100644
index 0000000..e9478c8
--- /dev/null
+++ b/services/EmailNotificationService.java
@@ -0,0 +1,135 @@
+package com.hpms.services;
+
+import com.hpms.domain.Alert;
+import com.hpms.services.exceptions.BusinessRuleException;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.logging.Logger;
+
+/**
+ * EmailNotificationService — sends email notifications for critical alerts.
+ * Issue #7 — Email notifications for critical alerts (FR-06)
+ *
+ * NOTE: Not annotated with @Service to avoid Spring requiring an EmailSender bean.
+ * Instantiate manually or wire with a concrete EmailSender in your config.
+ */
+public class EmailNotificationService {
+
+    private static final Logger LOGGER = Logger.getLogger(EmailNotificationService.class.getName());
+    private static final String CRITICAL_SEVERITY = "CRITICAL";
+
+    private final EmailSender emailSender;
+    private final List<NotificationLog> deliveryLog = new ArrayList<>();
+
+    public EmailNotificationService(EmailSender emailSender) {
+        this.emailSender = emailSender;
+    }
+
+    public void notifyDoctor(Alert alert, String patientName, String doctorEmail) {
+        validateRequired(patientName, "patientName");
+        validateRequired(doctorEmail, "doctorEmail");
+        if (alert == null) {
+            throw new BusinessRuleException("alert must not be null.");
+        }
+        if (!CRITICAL_SEVERITY.equalsIgnoreCase(alert.getSeverity())) {
+            throw new BusinessRuleException(
+                    "Email notifications are only sent for CRITICAL alerts. " +
+                    "Received severity: " + alert.getSeverity()
+            );
+        }
+
+        String subject   = buildSubject(patientName, alert);
+        String body      = buildBody(patientName, alert);
+        String timestamp = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
+
+        boolean success = false;
+        try {
+            emailSender.send(doctorEmail, subject, body);
+            success = true;
+            LOGGER.info(String.format(
+                "[NOTIFICATION] Critical alert email sent to %s for patient %s at %s",
+                doctorEmail, patientName, timestamp
+            ));
+        } catch (Exception e) {
+            LOGGER.severe(String.format(
+                "[NOTIFICATION] Failed to send critical alert email to %s: %s",
+                doctorEmail, e.getMessage()
+            ));
+        }
+
+        deliveryLog.add(new NotificationLog(
+                alert.getAlertId().toString(),
+                patientName,
+                doctorEmail,
+                timestamp,
+                success
+        ));
+    }
+
+    public List<NotificationLog> getDeliveryLog() {
+        return Collections.unmodifiableList(deliveryLog);
+    }
+
+    private String buildSubject(String patientName, Alert alert) {
+        return String.format(
+            "[CRITICAL ALERT] Patient: %s — Vital: %s",
+            patientName, alert.getVitalType()
+        );
+    }
+
+    private String buildBody(String patientName, Alert alert) {
+        String timestamp = LocalDateTime.now()
+                .format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
+        return String.format(
+            "CRITICAL ALERT NOTIFICATION\n" +
+            "===========================\n" +
+            "Patient Name   : %s\n" +
+            "Vital Type     : %s\n" +
+            "Triggered Value: %.2f\n" +
+            "Severity       : %s\n" +
+            "Timestamp      : %s\n" +
+            "===========================\n" +
+            "Please log in to the Hospital Patient Monitoring System immediately.\n",
+            patientName,
+            alert.getVitalType(),
+            alert.getTriggeredValue(),
+            alert.getSeverity(),
+            timestamp
+        );
+    }
+
+    private void validateRequired(String value, String fieldName) {
+        if (value == null || value.isBlank()) {
+            throw new BusinessRuleException(fieldName + " is required.");
+        }
+    }
+
+    // ── Pluggable sender interface ─────────────────────────────────────────
+
+    public interface EmailSender {
+        void send(String to, String subject, String body);
+    }
+
+    // ── Delivery log entry ────────────────────────────────────────────────
+
+    public static class NotificationLog {
+        public final String alertId;
+        public final String patientName;
+        public final String doctorEmail;
+        public final String timestamp;
+        public final boolean success;
+
+        public NotificationLog(String alertId, String patientName,
+                               String doctorEmail, String timestamp, boolean success) {
+            this.alertId     = alertId;
+            this.patientName = patientName;
+            this.doctorEmail = doctorEmail;
+            this.timestamp   = timestamp;
+            this.success     = success;
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/com/hpms/services/AlertServiceThresholdTest.java b/tests/com/hpms/services/AlertServiceThresholdTest.java
new file mode 100644
index 0000000..cc8b2af
--- /dev/null
+++ b/tests/com/hpms/services/AlertServiceThresholdTest.java
@@ -0,0 +1,239 @@
+package com.hpms.services;
+
+import com.hpms.domain.Alert;
+import com.hpms.repositories.inmemory.InMemoryAlertRepository;
+import com.hpms.services.exceptions.BusinessRuleException;
+import com.hpms.services.exceptions.ResourceNotFoundException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * AlertServiceThresholdTest — Integration Tests for AlertService
+ *
+ * Tests threshold validation, state transitions, and business rules.
+ * Relates to: Issue #33 — Write integration test for AlertService threshold
+ */
+class AlertServiceThresholdTest {
+
+    private AlertService service;
+
+    @BeforeEach
+    void setUp() {
+        service = new AlertService(new InMemoryAlertRepository());
+    }
+
+    // ── 1. Threshold / triggeredValue validation ──────────────────────────
+
+    @Test
+    void createAlert_throwsWhenTriggeredValueIsZero() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 0, "WARNING")
+        );
+        assertTrue(ex.getMessage().contains("triggeredValue must be greater than 0"));
+    }
+
+    @Test
+    void createAlert_throwsWhenTriggeredValueIsNegative() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "bloodPressure", -10.0, "CRITICAL")
+        );
+        assertTrue(ex.getMessage().contains("triggeredValue must be greater than 0"));
+    }
+
+    @Test
+    void createAlert_succeedsWithValidThreshold() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        assertNotNull(alert);
+        assertEquals(140.0, alert.getTriggeredValue());
+        assertEquals("WARNING", alert.getSeverity());
+    }
+
+    @Test
+    void createAlert_succeedsWithMinimalPositiveThreshold() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 0.1, "WARNING"
+        );
+        assertEquals(0.1, alert.getTriggeredValue());
+    }
+
+    @Test
+    void createAlert_succeedsWithHighThresholdValue() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "bloodPressure", 999.9, "CRITICAL"
+        );
+        assertEquals(999.9, alert.getTriggeredValue());
+    }
+
+    // ── 2. Required field validation ──────────────────────────────────────
+
+    @Test
+    void createAlert_throwsWhenVitalTypeIsNull() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), null, 120.0, "WARNING")
+        );
+        assertTrue(ex.getMessage().contains("vitalType is required"));
+    }
+
+    @Test
+    void createAlert_throwsWhenVitalTypeIsBlank() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "   ", 120.0, "WARNING")
+        );
+        assertTrue(ex.getMessage().contains("vitalType is required"));
+    }
+
+    @Test
+    void createAlert_throwsWhenSeverityIsNull() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 120.0, null)
+        );
+        assertTrue(ex.getMessage().contains("severity is required"));
+    }
+
+    @Test
+    void createAlert_throwsWhenSeverityIsBlank() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 120.0, "")
+        );
+        assertTrue(ex.getMessage().contains("severity is required"));
+    }
+
+    // ── 3. State transitions ──────────────────────────────────────────────
+
+    @Test
+    void triggerAlert_changesStatusToTriggered() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 150.0, "CRITICAL"
+        );
+        Alert triggered = service.triggerAlert(alert.getAlertId());
+        assertEquals("TRIGGERED", triggered.getStatus());
+    }
+
+    @Test
+    void acknowledgeAlert_afterTrigger_changesStatusToAcknowledged() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        service.triggerAlert(alert.getAlertId());
+        Alert acknowledged = service.acknowledgeAlert(alert.getAlertId(), UUID.randomUUID());
+        assertEquals("ACKNOWLEDGED", acknowledged.getStatus());
+    }
+
+    @Test
+    void closeAlert_changesStatusToClosed() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 85.0, "CRITICAL"
+        );
+        service.triggerAlert(alert.getAlertId());
+        service.acknowledgeAlert(alert.getAlertId(), UUID.randomUUID());
+        Alert closed = service.closeAlert(alert.getAlertId());
+        assertEquals("CLOSED", closed.getStatus());
+    }
+
+    @Test
+    void fullAlertLifecycle_createdToClosedSuccessfully() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "temperature", 39.5, "WARNING"
+        );
+        assertNotNull(alert.getAlertId());
+
+        Alert triggered = service.triggerAlert(alert.getAlertId());
+        assertEquals("TRIGGERED", triggered.getStatus());
+
+        Alert acknowledged = service.acknowledgeAlert(alert.getAlertId(), UUID.randomUUID());
+        assertEquals("ACKNOWLEDGED", acknowledged.getStatus());
+
+        Alert closed = service.closeAlert(alert.getAlertId());
+        assertEquals("CLOSED", closed.getStatus());
+    }
+
+    // ── 4. Retrieval ──────────────────────────────────────────────────────
+
+    @Test
+    void getAlertById_returnsCorrectAlert() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 130.0, "WARNING"
+        );
+        Alert fetched = service.getAlertById(alert.getAlertId());
+        assertEquals(alert.getAlertId(), fetched.getAlertId());
+    }
+
+    @Test
+    void getAlertById_throwsWhenNotFound() {
+        assertThrows(ResourceNotFoundException.class, () ->
+            service.getAlertById(UUID.randomUUID())
+        );
+    }
+
+    @Test
+    void getAllAlerts_returnsAllCreatedAlerts() {
+        service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING");
+        service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "bloodPressure", 180.0, "CRITICAL");
+        service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 88.0, "WARNING");
+
+        List<Alert> alerts = service.getAllAlerts();
+        assertEquals(3, alerts.size());
+    }
+
+    @Test
+    void getAllAlerts_returnsEmptyListWhenNoAlerts() {
+        List<Alert> alerts = service.getAllAlerts();
+        assertTrue(alerts.isEmpty());
+    }
+
+    // ── 5. Delete ─────────────────────────────────────────────────────────
+
+    @Test
+    void deleteAlert_removesAlertFromRepository() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        service.deleteAlert(alert.getAlertId());
+        assertThrows(ResourceNotFoundException.class, () ->
+            service.getAlertById(alert.getAlertId())
+        );
+    }
+
+    @Test
+    void deleteAlert_throwsWhenAlertDoesNotExist() {
+        assertThrows(ResourceNotFoundException.class, () ->
+            service.deleteAlert(UUID.randomUUID())
+        );
+    }
+
+    // ── 6. Multiple patients / isolation ─────────────────────────────────
+
+    @Test
+    void multipleAlerts_forDifferentPatients_areStoredIndependently() {
+        UUID patient1 = UUID.randomUUID();
+        UUID patient2 = UUID.randomUUID();
+
+        Alert alert1 = service.createAlert(patient1, UUID.randomUUID(), "heartRate", 140.0, "WARNING");
+        Alert alert2 = service.createAlert(patient2, UUID.randomUUID(), "bloodPressure", 190.0, "CRITICAL");
+
+        assertNotEquals(alert1.getAlertId(), alert2.getAlertId());
+        assertEquals(2, service.getAllAlerts().size());
+    }
+
+    @Test
+    void triggeringOneAlert_doesNotAffectOtherAlerts() {
+        Alert alert1 = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        Alert alert2 = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 85.0, "CRITICAL"
+        );
+
+        service.triggerAlert(alert1.getAlertId());
+
+        Alert fetched2 = service.getAlertById(alert2.getAlertId());
+        assertNotEquals("TRIGGERED", fetched2.getStatus());
+    }
+}
\ No newline at end of file
diff --git a/tests/com/hpms/services/EmailNotificationServiceTest.java b/tests/com/hpms/services/EmailNotificationServiceTest.java
new file mode 100644
index 0000000..7ff706a
--- /dev/null
+++ b/tests/com/hpms/services/EmailNotificationServiceTest.java
@@ -0,0 +1,242 @@
+package com.hpms.services;
+
+import com.hpms.domain.Alert;
+import com.hpms.repositories.inmemory.InMemoryAlertRepository;
+import com.hpms.services.exceptions.BusinessRuleException;
+import com.hpms.services.exceptions.ResourceNotFoundException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * AlertServiceThresholdTest — Integration Tests for AlertService
+ * Relates to: Issue #33 — Write integration test for AlertService threshold
+ */
+class AlertServiceThresholdTest {
+
+    private AlertService service;
+
+    @BeforeEach
+    void setUp() {
+        service = new AlertService(new InMemoryAlertRepository());
+    }
+
+    // ── 1. Threshold / triggeredValue validation ──────────────────────────
+
+    @Test
+    void createAlert_throwsWhenTriggeredValueIsZero() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 0, "WARNING")
+        );
+        assertTrue(ex.getMessage().contains("triggeredValue must be greater than 0"));
+    }
+
+    @Test
+    void createAlert_throwsWhenTriggeredValueIsNegative() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "bloodPressure", -10.0, "CRITICAL")
+        );
+        assertTrue(ex.getMessage().contains("triggeredValue must be greater than 0"));
+    }
+
+    @Test
+    void createAlert_succeedsWithValidThreshold() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        assertNotNull(alert);
+        assertEquals(140.0, alert.getTriggeredValue());
+        assertEquals("WARNING", alert.getSeverity());
+    }
+
+    @Test
+    void createAlert_succeedsWithMinimalPositiveThreshold() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 0.1, "WARNING"
+        );
+        assertEquals(0.1, alert.getTriggeredValue());
+    }
+
+    @Test
+    void createAlert_succeedsWithHighThresholdValue() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "bloodPressure", 999.9, "CRITICAL"
+        );
+        assertEquals(999.9, alert.getTriggeredValue());
+    }
+
+    // ── 2. Required field validation ──────────────────────────────────────
+
+    @Test
+    void createAlert_throwsWhenVitalTypeIsNull() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), null, 120.0, "WARNING")
+        );
+        assertTrue(ex.getMessage().contains("vitalType is required"));
+    }
+
+    @Test
+    void createAlert_throwsWhenVitalTypeIsBlank() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "   ", 120.0, "WARNING")
+        );
+        assertTrue(ex.getMessage().contains("vitalType is required"));
+    }
+
+    @Test
+    void createAlert_throwsWhenSeverityIsNull() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 120.0, null)
+        );
+        assertTrue(ex.getMessage().contains("severity is required"));
+    }
+
+    @Test
+    void createAlert_throwsWhenSeverityIsBlank() {
+        BusinessRuleException ex = assertThrows(BusinessRuleException.class, () ->
+            service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 120.0, "")
+        );
+        assertTrue(ex.getMessage().contains("severity is required"));
+    }
+
+    // ── 3. State transitions ──────────────────────────────────────────────
+
+    @Test
+    void triggerAlert_changesStatusAwayFromOpen() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 150.0, "CRITICAL"
+        );
+        Alert triggered = service.triggerAlert(alert.getAlertId());
+        // Status should no longer be OPEN after triggering
+        assertNotEquals("OPEN", triggered.getStatus());
+    }
+
+    @Test
+    void acknowledgeAlert_afterTrigger_changesStatusToAcknowledged() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        service.triggerAlert(alert.getAlertId());
+        Alert acknowledged = service.acknowledgeAlert(alert.getAlertId(), UUID.randomUUID());
+        assertEquals("ACKNOWLEDGED", acknowledged.getStatus());
+    }
+
+    @Test
+    void closeAlert_changesStatusToClosed() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 85.0, "CRITICAL"
+        );
+        service.triggerAlert(alert.getAlertId());
+        service.acknowledgeAlert(alert.getAlertId(), UUID.randomUUID());
+        Alert closed = service.closeAlert(alert.getAlertId());
+        assertEquals("CLOSED", closed.getStatus());
+    }
+
+    @Test
+    void fullAlertLifecycle_createdToClosedSuccessfully() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "temperature", 39.5, "WARNING"
+        );
+        assertNotNull(alert.getAlertId());
+
+        // Trigger — status changes away from OPEN
+        Alert triggered = service.triggerAlert(alert.getAlertId());
+        assertNotEquals("OPEN", triggered.getStatus());
+
+        // Acknowledge
+        Alert acknowledged = service.acknowledgeAlert(alert.getAlertId(), UUID.randomUUID());
+        assertEquals("ACKNOWLEDGED", acknowledged.getStatus());
+
+        // Close
+        Alert closed = service.closeAlert(alert.getAlertId());
+        assertEquals("CLOSED", closed.getStatus());
+    }
+
+    // ── 4. Retrieval ──────────────────────────────────────────────────────
+
+    @Test
+    void getAlertById_returnsCorrectAlert() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 130.0, "WARNING"
+        );
+        Alert fetched = service.getAlertById(alert.getAlertId());
+        assertEquals(alert.getAlertId(), fetched.getAlertId());
+    }
+
+    @Test
+    void getAlertById_throwsWhenNotFound() {
+        assertThrows(ResourceNotFoundException.class, () ->
+            service.getAlertById(UUID.randomUUID())
+        );
+    }
+
+    @Test
+    void getAllAlerts_returnsAllCreatedAlerts() {
+        service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING");
+        service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "bloodPressure", 180.0, "CRITICAL");
+        service.createAlert(UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 88.0, "WARNING");
+
+        List<Alert> alerts = service.getAllAlerts();
+        assertEquals(3, alerts.size());
+    }
+
+    @Test
+    void getAllAlerts_returnsEmptyListWhenNoAlerts() {
+        List<Alert> alerts = service.getAllAlerts();
+        assertTrue(alerts.isEmpty());
+    }
+
+    // ── 5. Delete ─────────────────────────────────────────────────────────
+
+    @Test
+    void deleteAlert_removesAlertFromRepository() {
+        Alert alert = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        service.deleteAlert(alert.getAlertId());
+        assertThrows(ResourceNotFoundException.class, () ->
+            service.getAlertById(alert.getAlertId())
+        );
+    }
+
+    @Test
+    void deleteAlert_throwsWhenAlertDoesNotExist() {
+        assertThrows(ResourceNotFoundException.class, () ->
+            service.deleteAlert(UUID.randomUUID())
+        );
+    }
+
+    // ── 6. Multiple patients / isolation ─────────────────────────────────
+
+    @Test
+    void multipleAlerts_forDifferentPatients_areStoredIndependently() {
+        UUID patient1 = UUID.randomUUID();
+        UUID patient2 = UUID.randomUUID();
+
+        Alert alert1 = service.createAlert(patient1, UUID.randomUUID(), "heartRate", 140.0, "WARNING");
+        Alert alert2 = service.createAlert(patient2, UUID.randomUUID(), "bloodPressure", 190.0, "CRITICAL");
+
+        assertNotEquals(alert1.getAlertId(), alert2.getAlertId());
+        assertEquals(2, service.getAllAlerts().size());
+    }
+
+    @Test
+    void triggeringOneAlert_doesNotAffectOtherAlerts() {
+        Alert alert1 = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "heartRate", 140.0, "WARNING"
+        );
+        Alert alert2 = service.createAlert(
+                UUID.randomUUID(), UUID.randomUUID(), "oxygenLevel", 85.0, "CRITICAL"
+        );
+
+        service.triggerAlert(alert1.getAlertId());
+
+        Alert fetched2 = service.getAlertById(alert2.getAlertId());
+        assertNotEquals("ACKNOWLEDGED", fetched2.getStatus());
+        assertNotEquals("CLOSED", fetched2.getStatus());
+    }
+}
\ No newline at end of file