Fix testing for Flask 3.1.0 changes.

Author: Peter Doggart

tests/conftest.py

@@ -44,7 +44,7 @@ def get_specs(self, prefix="", status=200, **kwargs):
 
 @pytest.fixture
 def app():
-    app = Flask(__name__)
+    app = Flask(__name__, subdomain_matching=True)
     app.test_client_class = TestClient
     yield app