diff --git a/konova/autocompletes.py b/konova/autocompletes.py
index 58844f3e..241143c0 100644
--- a/konova/autocompletes.py
+++ b/konova/autocompletes.py
@@ -70,7 +70,7 @@ class ShareUserAutocomplete(Select2QuerySetView):
     def get_queryset(self):
         if self.request.user.is_anonymous:
             return User.objects.none()
-        exclude_user_ids = self.forwarded.get("users", [None])
+        exclude_user_ids = self.forwarded.get("users", [])
         _exclude = {"id__in": exclude_user_ids}
         qs = User.objects.all().exclude(
             **_exclude
@@ -78,6 +78,7 @@ class ShareUserAutocomplete(Select2QuerySetView):
             "username"
         )
         if self.q:
+            # Due to privacy concerns only a full username match will return the proper user entry
             qs = qs.filter(
                 username=self.q
             )
diff --git a/konova/tests/test_autocompletes.py b/konova/tests/test_autocompletes.py
new file mode 100644
index 00000000..06dffaab
--- /dev/null
+++ b/konova/tests/test_autocompletes.py
@@ -0,0 +1,35 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: michel.peltriaux@sgdnord.rlp.de
+Created on: 14.12.21
+
+"""
+import json
+
+from django.urls import reverse
+
+from konova.tests.test_views import BaseTestCase
+from django.test.client import Client
+
+
+class AutocompleteTestCase(BaseTestCase):
+    @classmethod
+    def setUpTestData(cls):
+        super().setUpTestData()
+        cls.client = Client()
+
+    def test_user_autocomplete(self):
+        self.client.login(username=self.superuser.username, password=self.superuser_pw)
+        user_autocomplete_url = reverse("share-user-autocomplete")
+        username = self.user.username
+        data = {
+            "q": username
+        }
+        response = self.client.get(
+            user_autocomplete_url,
+            data,
+        )
+        content = json.loads(response.content)
+        self.assertEqual(username, content["results"][0]["text"])
+        self.assertEqual(str(self.user.id), content["results"][0]["id"])