Add tests for EmailTemplate and NotificationLog models

Introduced comprehensive unit tests for EmailTemplate and NotificationLog, including creation, field validation, and custom methods. Added relevant test fixtures to support these models and expanded `conftest.py` for reusability. Validates functionality and maintains model integrity.

backend/tests/conftest.py

@@ -5,7 +5,8 @@ from datetime import datetime, timezone
 import pytest
 
 from app.models import GiftItem, GiftStatus, GiftPriority, RSVP, RSVPStatus, EventMedia, MediaType, MediaPurpose, \
-    EventTheme, Guest, GuestStatus, ActivityType, ActivityLog
+    EventTheme, Guest, GuestStatus, ActivityType, ActivityLog, EmailTemplate, TemplateType, NotificationLog, \
+    NotificationType, NotificationStatus
 from app.models.user import User
 from app.utils.test_utils import setup_test_db, teardown_test_db
 
@@ -193,3 +194,48 @@ def activity_log_fixture(db_session, mock_user, guest_fixture):
     db_session.add(activity_log_entry)
     db_session.commit()
     return activity_log_entry
+
+
+@pytest.fixture
+def email_template_fixture(db_session, mock_user):
+    """
+    Fixture to create and return a default EmailTemplate instance.
+    """
+    email_template = EmailTemplate(
+        id=uuid.uuid4(),
+        name="Invitation Template",
+        description="A template for event invitations.",
+        template_type=TemplateType.INVITATION,
+        subject="You're invited to {{event_name}}!",
+        html_content="<h1>Welcome to {{event_name}}</h1><p>We look forward to seeing you!</p>",
+        text_content="Welcome to {{event_name}}. We look forward to seeing you!",
+        variables={"event_name": "Birthday Party"},
+        event_id=None,  # Global template
+        created_by=mock_user.id,
+        is_active=True,
+        is_system=False,
+    )
+    db_session.add(email_template)
+    db_session.commit()
+    return email_template
+
+@pytest.fixture
+def notification_log_fixture(db_session, email_template_fixture, guest_fixture):
+    """
+    Fixture to create and return a default NotificationLog entry.
+    """
+    notification_log = NotificationLog(
+        id=uuid.uuid4(),
+        notification_type=NotificationType.EMAIL,
+        status=NotificationStatus.QUEUED,
+        subject="You're invited!",
+        content_preview="Join us for an unforgettable event.",
+        template_id=email_template_fixture.id,
+        event_id=guest_fixture.event_id,
+        guest_id=guest_fixture.id,
+        recipient="example@example.com",
+        notification_metadata={"extra_info": "Email sent via SendGrid"},
+    )
+    db_session.add(notification_log)
+    db_session.commit()
+    return notification_log