diff --git a/src/wuttaweb/testing.py b/src/wuttaweb/testing.py
index 22b4cf3..3a189a2 100644
--- a/src/wuttaweb/testing.py
+++ b/src/wuttaweb/testing.py
@@ -139,7 +139,7 @@ class VersionWebTestCase(WebTestCase):
         continuum.versioning_manager.transaction_cls = continuum.TransactionFactory()
         self.teardown_web()
 
-    def make_config(self, **kwargs):
+    def make_config(self, files=None, **kwargs):
         """
         Make and customize the config object.
 
@@ -149,7 +149,7 @@ class VersionWebTestCase(WebTestCase):
             WuttaContinuumConfigExtension,
         )
 
-        config = super().make_config(**kwargs)
+        config = super().make_config(files, **kwargs)
         config.setdefault("wutta_continuum.enable_versioning", "true")
 
         # nb. must purge model classes from sys.modules, so they will