def METHOD_NAME(self):
    # Check that a variable emulation object passes its real data directly.
    emulated_data = mock.Mock()
    # Make a cf_var with a special extra '_data_array' property.
    cf_var = self._make(chunksizes=None, _data_array=emulated_data)
    result = _get_cf_var_data(cf_var, self.filename)
    # This should get directly returned.
    self.assertIs(emulated_data, result)