class_docstr: Groupwise RankingEstimator tests.
code: def tearDown(self):
      super(GroupwiseRankingEstimatorTest, self).tearDown()
      if self._model_dir:
          tf.io.gfile.rmtree(self._model_dir)
      self._model_dir = None
      self._estimator = None
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from absl.testing import parameterized
  import tensorflow
  from tensorflow import estimator
  from tensorflow_ranking.python import feature
  from tensorflow_ranking.python import head
  from tensorflow_ranking.python import losses
  from tensorflow_ranking.python import model
label_desc: Use image node_id 2 for calling the GroupwiseRankingEstimatorTest obj's underlying member method code with example usage: obj.tearDown() without return types