docstr: ipyparallel.register_joblib_backend() registers default backend
code: def test_default_backend(self):
      """ipyparallel.register_joblib_backend() registers default backend"""
      ipp.register_joblib_backend()
      with mock.patch.object(
          ipp.Client, "__new__", lambda *a, **kw: self.client
      ):
          p = Parallel(backend="ipyparallel")
          assert p._backend._view.client is self.client
  
file_path: ipyparallel/ipyparallel/tests/test_joblib.py
imports: import warnings
  from unittest import mock
  import pytest
  import ipyparallel
  from .clienttest import ClusterTestCase, add_engines
label_desc: Use image node_id 2 for calling the TestJobLib obj's underlying member method code with example usage: obj.test_default_backend() without return types