def METHOD_NAME(self, iwsd):
    """Test saving a dataset without unit conversion."""
    from satpy.writers.ninjotiff import NinjoTIFFWriter
    ntw = NinjoTIFFWriter()
    dataset = xr.DataArray([1, 2, 3], attrs={'units': 'K'})
    with mock.patch('satpy.writers.ninjotiff.convert_units') as uconv:
        ntw.save_dataset(dataset, physic_unit='CELSIUS',
                         convert_temperature_units=False)
        uconv.assert_not_called()
    self.assertEqual(iwsd.call_count, 1)