1 files changed, 4 insertions, 0 deletions
diff --git a/tests/utils.py b/tests/utils.py
index 5e4d77920c..d378de7b41 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -79,6 +79,10 @@ def setup_test_homeserver(name="test", datastore=None, config=None, reactor=None
         config.max_mau_value = 50
         config.mau_limits_reserved_threepids = []
 
+        # we need a sane default_room_version, otherwise attempts to create rooms will
+        # fail.
+        config.default_room_version = "1"
+
         # disable user directory updates, because they get done in the
         # background, which upsets the test runner.
         config.update_user_directory = False