docstr: Tests the value of GIT_COMMIT env. var is returned
  if MXNET_SHA env var is not present
docstr_tok: ["Tests","the","value","of","GIT_COMMIT","env",".","var","is","returned","if","MXNET_SHA","env","var","is","not","present"]
code: def test_probe_commit_id_git_commit(self):
      """
      Tests the value of GIT_COMMIT env. var is returned
      if MXNET_SHA env var is not present
      """
      with patch.dict("os.environ", {"GIT_COMMIT": "abcd1234"}):
          self.assertEqual(probe_commit_id(), "abcd1234")
  
      with patch.dict(
          "os.environ",
          {"MXNET_SHA": "efgh5678", "GIT_COMMIT": "abcd1234"},
      ):
          self.assertEqual(probe_commit_id(), "efgh5678")
  
imports: import unittest
  from unittest.mock import MagicMock, mock_open, patch
  from artifact_repository import *
label_desc: Use image node_id 4 for calling the TestArtifactRepositoryTool obj's underlying member method code with example usage: obj.test_probe_commit_id_git_commit() without return types