new_contents: import pytest
  from xenon import Path
  from xenon.exceptions import NoSuchPathException
  
  
  def test_file_does_not_exist(local_filesystem, tmpdir):
      tmpdir = Path(str(tmpdir))
      with pytest.raises(NoSuchPathException):
          filename = tmpdir / 'this-file-does-not-exist'
          result = bytearray()
          for chunk in local_filesystem.read_from_file(filename):
              result.extend(chunk)
  
subject: add new unittest for issue #28