'Test directly SingletonImportTask.lookup_candidates().'

def test_candidates_singleton(self):

    task = importer.SingletonImportTask(toppath='top    path', item=_common.item())
    task.search_ids = [(self.MB_RECORDING_PREFIX + self.ID_RECORDING_0), (self.MB_RECORDING_PREFIX + self.ID_RECORDING_1), 'an    invalid    and    discarded    id']
    task.lookup_candidates()
    self.assertEqual(set(['VALID_RECORDING_0', 'VALID_RECORDING_1']), set([c.info.title for c in task.candidates]))
