diff --git a/compensation/models/compensation.py b/compensation/models/compensation.py
index 33c2008..0ae03fe 100644
--- a/compensation/models/compensation.py
+++ b/compensation/models/compensation.py
@@ -21,7 +21,7 @@ from compensation.utils.quality import CompensationQualityChecker
 from konova.models import BaseObject, AbstractDocument, Deadline, generate_document_file_upload_path, \
     GeoReferencedMixin, DeadlineType, ResubmitableObjectMixin
 from konova.utils.message_templates import DATA_UNSHARED_EXPLANATION, COMPENSATION_REMOVED_TEMPLATE, \
-    DOCUMENT_REMOVED_TEMPLATE, DEADLINE_REMOVED, ADDED_DEADLINE, \
+    DOCUMENT_REMOVED_TEMPLATE, DEADLINE_REMOVED, DEADLINE_ADDED, \
     COMPENSATION_ACTION_REMOVED, COMPENSATION_STATE_REMOVED, INTERVENTION_HAS_REVOCATIONS_TEMPLATE
 from user.models import UserActionLogEntry
 
@@ -75,7 +75,7 @@ class AbstractCompensation(BaseObject,
 
             self.save()
             self.deadlines.add(deadline)
-            self.mark_as_edited(user, edit_comment=ADDED_DEADLINE)
+            self.mark_as_edited(user, edit_comment=DEADLINE_ADDED)
             return deadline
 
     def remove_deadline(self, form):
diff --git a/konova/tests/unit/__init__.py b/konova/tests/unit/__init__.py
new file mode 100644
index 0000000..4ebfb7e
--- /dev/null
+++ b/konova/tests/unit/__init__.py
@@ -0,0 +1,7 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: ksp-servicestelle@sgdnord.rlp.de
+Created on: 29.08.23
+
+"""
diff --git a/konova/tests/unit/test_deadline.py b/konova/tests/unit/test_deadline.py
new file mode 100644
index 0000000..1da9801
--- /dev/null
+++ b/konova/tests/unit/test_deadline.py
@@ -0,0 +1,118 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: ksp-servicestelle@sgdnord.rlp.de
+Created on: 29.08.23
+
+"""
+from django.test import RequestFactory
+from django.utils.timezone import now
+from django.utils.translation import gettext_lazy as _
+
+from compensation.forms.modals.deadline import NewDeadlineModalForm, EditDeadlineModalForm
+from konova.models import DeadlineType
+from konova.tests.test_views import BaseTestCase
+from konova.utils.generators import generate_random_string
+from konova.utils.message_templates import DEADLINE_ADDED, DEADLINE_EDITED
+from user.models import UserAction
+
+
+class NewDeadlineModalFormTestCase(BaseTestCase):
+    def setUp(self) -> None:
+        super().setUp()
+        self.request = RequestFactory().request()
+        self.request.user = self.superuser
+        self.today = now().date()
+
+    def test_init(self):
+        form = NewDeadlineModalForm(request=self.request, instance=self.compensation)
+        self.assertEqual(form.form_title, str(_("New deadline")))
+        self.assertEqual(form.form_caption, str(_("Insert data for the new deadline")))
+        self.assertEqual(form.user, self.superuser)
+        self.assertEqual(form.request, self.request)
+
+    def test_is_valid(self):
+        data = {
+            "type": DeadlineType.MAINTAIN,
+            "date": self.today,
+            "comment": "",
+        }
+        form = NewDeadlineModalForm(
+            data,
+            request=self.request,
+            instance=self.compensation
+        )
+        self.assertTrue(form.is_valid())
+
+        data["type"] = DeadlineType.OTHER
+        form = NewDeadlineModalForm(
+            data,
+            request=self.request,
+            instance=self.compensation
+        )
+        self.assertFalse(form.is_valid(), msg=form.errors)
+        self.assertTrue(form.has_error("comment"))
+        _error = form.errors["comment"]
+        self.assertEqual(len(_error), 1)
+        self.assertEqual(_error[0], str(_("Please explain this 'other' type of deadline.")))
+
+        data["comment"] = "Test"
+        data["type"] = DeadlineType.OTHER
+        form = NewDeadlineModalForm(
+            data,
+            request=self.request,
+            instance=self.compensation
+        )
+        self.assertTrue(form.is_valid())
+
+    def test_save(self):
+        data = {
+            "type": DeadlineType.MAINTAIN,
+            "date": self.today,
+            "comment": generate_random_string(length=20, use_letters_lc=True),
+        }
+        form = NewDeadlineModalForm(
+            data,
+            request=self.request,
+            instance=self.compensation
+        )
+        self.assertTrue(form.is_valid(), msg=form.errors)
+        deadline = form.save()
+        self.assertEqual(deadline.type, data["type"])
+        self.assertEqual(deadline.date, data["date"])
+        self.assertEqual(deadline.comment, data["comment"])
+        self.assertIn(deadline, self.compensation.deadlines.all())
+
+        last_log = self.compensation.log.first()
+        self.assertEqual(last_log.user, self.superuser)
+        self.assertEqual(last_log.action, UserAction.EDITED)
+        self.assertEqual(last_log.comment, DEADLINE_ADDED)
+
+
+class EditDeadlineModalFormTestCase(NewDeadlineModalFormTestCase):
+    def setUp(self) -> None:
+        super().setUp()
+
+    def test_save(self):
+        data = {
+            "type": DeadlineType.MAINTAIN,
+            "date": self.today,
+            "comment": generate_random_string(length=20, use_letters_lc=True),
+        }
+        form = EditDeadlineModalForm(
+            data,
+            request=self.request,
+            instance=self.compensation,
+            deadline=self.finished_deadline,
+        )
+
+        self.assertTrue(form.is_valid(), msg=form.errors)
+        deadline = form.save()
+        self.assertEqual(deadline.type, data["type"])
+        self.assertEqual(deadline.date, data["date"])
+        self.assertEqual(deadline.comment, data["comment"])
+
+        last_log = self.compensation.log.first()
+        self.assertEqual(last_log.action, UserAction.EDITED)
+        self.assertEqual(last_log.user, self.superuser)
+        self.assertEqual(last_log.comment, DEADLINE_EDITED)
diff --git a/konova/utils/message_templates.py b/konova/utils/message_templates.py
index 6e8fa65..6dcaa33 100644
--- a/konova/utils/message_templates.py
+++ b/konova/utils/message_templates.py
@@ -79,7 +79,6 @@ DOCUMENT_EDITED = _("Document edited")
 
 # Edited
 EDITED_GENERAL_DATA = _("Edited general data")
-ADDED_DEADLINE = _("Added deadline")
 
 # Geometry
 GEOMETRY_CONFLICT_WITH_TEMPLATE = _("Geometry conflict detected with {}")