code: def testAll2(self):
      greq = MPI.Grequest.Start(None, None, None)
      self.assertFalse(greq.Test())
      greq.Cancel()
      greq.Complete()
      status = MPI.Status()
      self.assertTrue(greq.Test(status))
      self.assertEqual(status.Get_source(), MPI.ANY_SOURCE)
      self.assertEqual(status.Get_tag(), MPI.ANY_TAG)
      self.assertEqual(status.Get_error(), MPI.SUCCESS)
      self.assertFalse(status.Is_cancelled())
      greq.Wait()
  
file_path: mpi4py/test/test_grequest.py
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 5 for calling the TestGrequest obj's underlying member method code with example usage: obj.testAll2() without return types