diff --git a/authens/tests/cas_utils.py b/authens/tests/cas_utils.py
index 089ffb7..76d862c 100644
--- a/authens/tests/cas_utils.py
+++ b/authens/tests/cas_utils.py
@@ -17,3 +17,27 @@ class FakeCASClient:
             )
         }
         return self.cas_login, attributes, None
+
+
+class FakeLDAPObject:
+    """Fake object to be used in place of the result of `ldap.initialize`.
+
+    By default, always return the same entry 'johndoe'.
+    """
+
+    def __init__(self, cas_login: str, entrance_year: int):
+        self.cas_login = cas_login
+        self.entrance_year = entrance_year
+
+    def search_s(self, base, scope, request, *args):
+        if request != "(uid={})".format(self.cas_login):
+            raise ValueError("I don't know how to answer this request!")
+
+        home_dir = "/users/{}/info/{}".format(self.entrance_year % 100, self.cas_login)
+        dn = "whatever"
+        attrs = {
+            "uid": [self.cas_login.encode("utf-8")],
+            "cn": ["{}'s long name".format(self.cas_login).encode("utf-8")],
+            "homeDirectory": [home_dir.encode("utf-8")],
+        }
+        return [(dn, attrs)]
diff --git a/authens/tests/test_shortcuts.py b/authens/tests/test_shortcuts.py
new file mode 100644
index 0000000..3c2a16b
--- /dev/null
+++ b/authens/tests/test_shortcuts.py
@@ -0,0 +1,47 @@
+from unittest import mock
+
+from django.contrib.auth import get_user_model
+from django.test import TestCase
+
+from authens.models import CASAccount, OldCASAccount
+from authens.shortcuts import register_cas_account
+from authens.tests.cas_utils import FakeLDAPObject
+
+User = get_user_model()
+
+
+class TestRegisterCasAccount(TestCase):
+    @mock.patch("authens.shortcuts.ldap.initialize")
+    def test_register(self, mock_ldap_obj):
+        mock_ldap_obj.return_value = FakeLDAPObject("johndoe", 2019)
+
+        user = User.objects.create_user(username="whatever")
+        self.assertFalse(hasattr(user, "cas_account"))
+
+        register_cas_account(user, cas_login="johndoe")
+        user.refresh_from_db()
+        self.assertTrue(hasattr(user, "cas_account"))
+        self.assertEqual(user.cas_account.cas_login, "johndoe")
+        self.assertEqual(user.cas_account.entrance_year, 2019)
+
+    def test_cant_register_twice(self):
+        user = User.objects.create_user(username="whatever")
+        CASAccount.objects.create(user=user, cas_login="johndoe", entrance_year=2019)
+
+        with self.assertRaises(ValueError):
+            register_cas_account(user, cas_login="johndoe")
+        with self.assertRaises(ValueError):
+            register_cas_account(user, cas_login="janisjoplin")
+
+        self.assertEqual(CASAccount.objects.count(), 1)
+
+    def test_cant_register_old_account(self):
+        user = User.objects.create_user(username="whatever")
+        OldCASAccount.objects.create(user=user, cas_login="toto", entrance_year=2012)
+
+        with self.assertRaises(ValueError):
+            register_cas_account(user, cas_login="toto")
+        with self.assertRaises(ValueError):
+            register_cas_account(user, cas_login="ninasimone")
+
+        self.assertFalse(CASAccount.objects.exists())