    def _default_url(self):
        """Use a default_url that any jupyter server will provide

        Should be:

        - authenticated, so we are testing auth
        - always available (i.e. in mocked ServerApp and NotebookApp)
        - *not* an API handler that raises 403 instead of redirecting
        """
        return "/tree"
Use a default_url that any jupyter server will provide

Should be:

- authenticated, so we are testing auth
- always available (i.e. in mocked ServerApp and NotebookApp)
- *not* an API handler that raises 403 instead of redirecting
jupyterhub/tests/mocking.py