code: def test_GitRepo_remote_update(path1=None, path2=None, path3=None):
      git1 = GitRepo(path1)
      git2 = GitRepo(path2)
      git3 = GitRepo(path3)
  
      git1.add_remote("git2", path2)
      git1.add_remote("git3", path3)
  
      # Setting up remote 'git2'
      with open(op.join(path2, "masterfile"), "w") as f:
          f.write("git2 in master")
      git2.add("masterfile")
      git2.commit("Add something to master.")
      git2.checkout("branch2", ["-b"])
      with open(op.join(path2, "branch2file"), "w") as f:
          f.write("git2 in branch2")
      git2.add("branch2file")
      git2.commit("Add something to branch2.")
  
      # Setting up remote 'git3'
      with open(op.join(path3, "masterfile"), "w") as f:
          f.write("git3 in master")
      git3.add("masterfile")
      git3.commit("Add something to master.")
      git3.checkout("branch3", ["-b"])
      with open(op.join(path3, "branch3file"), "w") as f:
          f.write("git3 in branch3")
      git3.add("branch3file")
      git3.commit("Add something to branch3.")
  
      git1.update_remote()
  
      # checkouts are 'tests' themselves, since they'll raise CommandError
      # if something went wrong
      git1.checkout("branch2")
      git1.checkout("branch3")
  
      branches1 = git1.get_branches()
      eq_({"branch2", "branch3"}, set(branches1))
  
imports: import logging
  import os
  import os.path
  import sys
  import pytest
  from datalad import get_encoding_info
  from datalad.cmd import StdOutCapture, StdOutErrCapture, WitlessRunner
  from datalad.support.exceptions import CommandError, FileNotInRepositoryError, InvalidGitRepositoryError, NoSuchPathError, PathKnownToRepositoryError
  from datalad.support.external_versions import external_versions
  from datalad.support.gitrepo import GitRepo, _normalize_path, normalize_paths, to_options
  from datalad.support.sshconnector import get_connection_hash
  from datalad.tests.utils_pytest import DEFAULT_BRANCH, DEFAULT_REMOTE, SkipTest, assert_cwd_unchanged, assert_equal, assert_false, assert_in, assert_in_results, assert_is_instance, assert_not_equal, assert_not_in, assert_raises, assert_repo_status, assert_true, create_tree, eq_, get_most_obscure_supported_name, integration, neq_, ok_, skip_if_no_network, skip_if_on_windows, skip_nomultiplex_ssh, slow, swallow_logs, with_tempfile, with_tree, xfail_buggy_annex_info
  from datalad.utils import Path, chpwd, getpwd, on_windows, rmtree
label_desc: Use image node_id 23 for calling a global function with example usage: test_GitRepo_remote_update(path1, path2, path3) without return types