def path(self):
    """Returns the build root for the current workspace."""
    if self._root_dir is None:
      # This env variable is for testing purpose.
      override_buildroot = os.environ.get('PANTS_BUILDROOT_OVERRIDE', None)
      if override_buildroot:
        self._root_dir = override_buildroot
      else:
        self._root_dir = os.path.realpath(self.find_buildroot())
      if PY2:
        self._root_dir = self._root_dir.decode('utf-8')
    return self._root_dir
Returns the build root for the current workspace.