diff --git a/helpdesk/tests/test_time_spent_auto.py b/helpdesk/tests/test_time_spent_auto.py
index 89c8a9e5..3dba8f25 100644
--- a/helpdesk/tests/test_time_spent_auto.py
+++ b/helpdesk/tests/test_time_spent_auto.py
@@ -1,5 +1,5 @@
 
-import datetime
+from datetime import datetime, timedelta
 from django.contrib.auth.hashers import make_password
 from django.contrib.auth.models import User
 from django.test import TestCase
@@ -17,51 +17,83 @@ class TimeSpentAutoTestCase(TestCase):
             title='Queue 1',
             slug='q1',
             allow_public_submission=True,
-            dedicated_time=datetime.timedelta(minutes=60)
+            dedicated_time=timedelta(minutes=60)
         )
 
-        self.ticket_data = {
-            'title': 'Test Ticket',
-            'description': 'Some Test Ticket',
-        }
-
-        ticket_data = dict(queue=self.queue_public, **self.ticket_data)
-        self.ticket = Ticket.objects.create(**ticket_data)
+        self.ticket_data = dict(queue=self.queue_public,
+                                title='test ticket',
+                                description='test ticket description')
 
         self.client = Client()
 
-        user1_kwargs = {
-            'username': 'staff',
-            'email': 'staff@example.com',
-            'password': make_password('Test1234'),
-            'is_staff': True,
-            'is_superuser': False,
-            'is_active': True
-        }
-        self.user = User.objects.create(**user1_kwargs)
-    
-    def test_add_followup_time_spent_auto(self):
-        """Tests automatic time_spent calculation."""
+        self.user = User.objects.create(
+            username='staff',
+            email='staff@example.com',
+            password=make_password('Test1234'),
+            is_staff=True,
+            is_superuser=False,
+            is_active=True
+        )
 
+    def test_add_two_followups_time_spent_auto(self):
+        """Tests automatic time_spent calculation"""
+        # activate automatic calculation
         helpdesk_settings.FOLLOWUP_TIME_SPENT_AUTO = True
 
-        message_id = uuid.uuid4().hex
-        followup = FollowUp.objects.create(
-            ticket=self.ticket,
-            date=self.ticket.created + datetime.timedelta(minutes=30),
-            title="Testing followup",
-            comment="Testing followup time spent",
-            public=True,
-            user=self.user,
-            new_status=1,
-            message_id=message_id,
-            time_spent=None
+        # ticket creation date, follow-up creation date, assertion value
+        TEST_VALUES = (
+            # friday
+            ('2024-03-01T00:00:00+00:00', '2024-03-01T09:30:10+00:00', timedelta(hours=9, minutes=30, seconds=10)),
+            ('2024-03-01T00:00:00+00:00', '2024-03-01T23:59:58+00:00', timedelta(hours=23, minutes=59, seconds=58)),
+            ('2024-03-01T00:00:00+00:00', '2024-03-01T23:59:59+00:00', timedelta(hours=24)),
+            ('2024-03-01T00:00:00+00:00', '2024-03-02T00:00:00+00:00', timedelta(hours=24)),
+            ('2024-03-01T00:00:00+00:00', '2024-03-02T09:00:00+00:00', timedelta(hours=33)),
+            ('2024-03-01T00:00:00+00:00', '2024-03-03T00:00:00+00:00', timedelta(hours=48)),
         )
-        followup.save()
 
-        self.assertEqual(followup.time_spent.seconds, 1800)
-        self.assertEqual(self.ticket.time_spent.seconds, 1800)
-        self.assertEqual(self.queue_public.time_spent.seconds, 1800)
-        self.assertTrue(
-            self.queue_public.dedicated_time.seconds > self.queue_public.time_spent.seconds
-        )
\ No newline at end of file
+        for (ticket_time, fup_time, assertion_delta) in TEST_VALUES:
+            # create and setup test ticket time
+            ticket = Ticket.objects.create(**self.ticket_data)
+            ticket_time = datetime.strptime(ticket_time, "%Y-%m-%dT%H:%M:%S%z")
+            ticket.created = ticket_time
+            ticket.modified = ticket_time
+            ticket.save()
+
+            fup_time = datetime.strptime(fup_time, "%Y-%m-%dT%H:%M:%S%z")
+            followup1 = FollowUp.objects.create(
+                ticket=ticket,
+                date=fup_time,
+                title="Testing followup",
+                comment="Testing followup time spent",
+                public=True,
+                user=self.user,
+                new_status=1,
+                message_id=uuid.uuid4().hex,
+                time_spent=None
+            )
+            followup1.save()
+
+            self.assertEqual(followup1.time_spent.total_seconds(), assertion_delta.total_seconds())
+            self.assertEqual(ticket.time_spent.total_seconds(), assertion_delta.total_seconds())
+
+            # adding a second follow-up 1 hour later
+            hour_delta = timedelta(hours=1)
+            followup2 = FollowUp.objects.create(
+                ticket=ticket,
+                date=followup1.date + hour_delta,
+                title="Testing followup 2",
+                comment="Testing followup time spent 2",
+                public=True,
+                user=self.user,
+                new_status=1,
+                message_id=uuid.uuid4().hex,
+                time_spent=None
+            )
+            followup2.save()
+
+            # we have a special case with the last second of the day being added if day ends at 23:59:59
+            day_overlap = followup2.date.toordinal() - followup1.date.toordinal()
+            hour_delta = hour_delta - timedelta(seconds=1 * day_overlap)
+
+            self.assertEqual(followup2.time_spent.total_seconds(), hour_delta.total_seconds())
+            self.assertEqual(ticket.time_spent.total_seconds(), assertion_delta.total_seconds() + hour_delta.total_seconds())
\ No newline at end of file