diff --git a/dj_rest_auth/tests/test_api.py b/dj_rest_auth/tests/test_api.py
index b6bba96..0f8ee42 100644
--- a/dj_rest_auth/tests/test_api.py
+++ b/dj_rest_auth/tests/test_api.py
@@ -630,7 +630,7 @@ class APIBasicTests(TestsMixin, TestCase):
     @override_settings(REST_SESSION_LOGIN=False)
     @override_settings(
         REST_AUTH_SERIALIZERS={
-            "JWT_TOKEN_CLAIMS_SERIALIZER": TESTTokenObtainPairSerializer
+            "JWT_TOKEN_CLAIMS_SERIALIZER": 'tests.test_api.TESTTokenObtainPairSerializer'
         }
     )
     def test_custom_jwt_claims(self):
@@ -659,7 +659,7 @@ class APIBasicTests(TestsMixin, TestCase):
     @override_settings(REST_SESSION_LOGIN=False)
     @override_settings(
         REST_AUTH_SERIALIZERS={
-            "JWT_TOKEN_CLAIMS_SERIALIZER": TESTTokenObtainPairSerializer
+            "JWT_TOKEN_CLAIMS_SERIALIZER": 'tests.test_api.TESTTokenObtainPairSerializer'
         }
     )
     def test_custom_jwt_claims_cookie_w_authentication(self):