diff --git a/tests/test_post_operation.py b/tests/test_post_operation.py
index a868792..3da88bf 100644
--- a/tests/test_post_operation.py
+++ b/tests/test_post_operation.py
@@ -66,7 +66,8 @@ def test_post_good_query_with_params(self, mocker):
             )
 
             config = {
-                'TARGET_BACKEND': 'uproot'
+                'TARGET_BACKEND': 'uproot',
+                'TRANSFORMER_SCIENCE_IMAGE': "foo/bar:latest"
             }
             app = create_app(config, provided_translator=mock_ast_translator)
             client = app.test_client()