diff --git a/tests/test_one_to_one_with_inheritance.py b/tests/test_one_to_one_with_inheritance.py
index 06e1cd8b8..9c489c1df 100644
--- a/tests/test_one_to_one_with_inheritance.py
+++ b/tests/test_one_to_one_with_inheritance.py
@@ -14,7 +14,7 @@ from tests.test_multitable_inheritance import ChildModel
 # Regression test for #4290
 
 class ChildAssociatedModel(RESTFrameworkModel):
-    child_model = models.OneToOneField(ChildModel)
+    child_model = models.OneToOneField(ChildModel, on_delete=models.CASCADE)
     child_name = models.CharField(max_length=100)