diff --git a/tests/app/service/test_rest.py b/tests/app/service/test_rest.py
index ba61fea32..b8bcd126e 100644
--- a/tests/app/service/test_rest.py
+++ b/tests/app/service/test_rest.py
@@ -887,7 +887,7 @@ def test_update_service_sets_volumes(
 @pytest.mark.parametrize('value, expected_status, expected_persisted', (
     (True, 200, True),
     (False, 200, False),
-    ('Yes', 400, None),
+    ('unknown', 400, None),
 ))
 def test_update_service_sets_research_consent(
     admin_request,