def test_local_repository
    in_temp_dir do
      git = Git.init('new_repo', initial_branch: 'main')
      FileUtils.cd('new_repo') do
        File.write('README.md', '# This is a README')
        git.add('README.md')
        git.commit('Initial commit')
      end
      FileUtils.touch('new_repo/README.md')

      assert_equal('main', @lib.repository_default_branch('new_repo'))
    end
  end
This is the one real test that actually calls git.  The rest of the tests
mock Git::Lib#command to return specific responses.