diff --git a/graphene_django/rest_framework/tests/test_mutation.py b/graphene_django/rest_framework/tests/test_mutation.py
index bfb2f17..58bc4ce 100644
--- a/graphene_django/rest_framework/tests/test_mutation.py
+++ b/graphene_django/rest_framework/tests/test_mutation.py
@@ -3,7 +3,7 @@ import datetime
 from pytest import raises
 from rest_framework import serializers
 
-from graphene import Field, ResolveInfo
+from graphene import Field, ResolveInfo, String
 from graphene.types.inputobjecttype import InputObjectType
 
 from ...types import DjangoObjectType