diff --git a/core/tests/test_subscription_assignment_service.py b/core/tests/test_subscription_assignment_service.py
index fd27054f9000b0f4fbfce0c09791450aa2fc2931..db9aa76e0beb8fd883dc7fc72674508999712979 100644
--- a/core/tests/test_subscription_assignment_service.py
+++ b/core/tests/test_subscription_assignment_service.py
@@ -254,6 +254,33 @@ class TestApiEndpoints(APITestCase):
         assignments = response.data['assignments']
         self.assertEqual(2, len(assignments))
 
+    def test_two_tutors_cant_have_assignments_for_same_submission(self):
+        client = APIClient()
+        client.force_authenticate(user=self.data['tutors'][0])
+
+        subscription = client.post('/api/subscription/',
+                                   {'query_type': 'random'}).data
+
+        assignment_fst_tutor = client.post(
+                '/api/assignment/', {
+                    'subscription': subscription['pk']
+                }
+            ).data
+
+        client.force_authenticate(user=self.data['tutors'][1])
+
+        subscription = client.post('/api/subscription/',
+                                   {'query_type': 'random'}).data
+
+        assignment_snd_tutor = client.post(
+            '/api/assignment/', {
+                'subscription': subscription['pk']
+            }
+        ).data
+
+        self.assertNotEqual(assignment_fst_tutor['submission']['pk'],
+                            assignment_snd_tutor['submission']['pk'])
+
     def test_all_stages_of_the_subscription(self):
         client = APIClient()
         client.force_authenticate(user=self.data['tutors'][0])