Test grandfather path.

lms/djangoapps/linkedin/management/commands/tests/test_mailusers.py

@@ -37,3 +37,28 @@ class MailusersTests(unittest.TestCase):
             [((fred.user, 1),),
              ((fred.user, 2),),
              ((barney.user, 3),)])
+
+    @mock.patch('linkedin.management.commands.mailusers.send_grandfather_email')
+    @mock.patch('linkedin.management.commands.mailusers.GeneratedCertificate')
+    @mock.patch('linkedin.management.commands.mailusers.LinkedIn')
+    def test_mail_users_grandfather(self, linkedin, certificates, send_email):
+        """
+        Test "happy path" for sending grandfather emails.
+        """
+        fut = mailusers.Command().handle
+        fred = mock.Mock(user=mock.Mock(certificates=[1, 2]))
+        barney = mock.Mock(user=mock.Mock(certificates=[3]))
+        linkedin.objects.filter.return_value = [fred, barney]
+
+        def filter_user(user):
+            "Mock querying the database."
+            queryset = mock.Mock()
+            queryset.filter.return_value = user.certificates
+            return queryset
+
+        certificates.objects.filter = filter_user
+        fut(grandfather=True)
+        self.assertEqual(
+            send_email.call_args_list,
+            [((fred.user, [1, 2]),),
+             ((barney.user, [3]),)])