docstr: Tests the value of MXNET_SHA env var is returned
docstr_tok: ["Tests","the","value","of","MXNET_SHA","env","var","is","returned"]
code: def test_probe_commit_id_mxnet_sha(self):
      """
      Tests the value of MXNET_SHA env var is returned
      """
      with patch.dict("os.environ", {"MXNET_SHA": "abcd1234"}):
          self.assertEqual(probe_commit_id(), "abcd1234")
  
imports: import unittest
  from unittest.mock import MagicMock, mock_open, patch
  from artifact_repository import *
label_desc: Use image node_id 3 for calling the TestArtifactRepositoryTool obj's underlying member method code with example usage: obj.test_probe_commit_id_mxnet_sha() without return types