def METHOD_NAME(self, mock_date_time):
    """Test purge is disabled."""
    session = self.populate_data()
    mock_date_time.get_utc_now_datetime.return_value = (
        datetime(2010, 12, 31))
    inventory_api = self.get_inventory_api()
    inventory_api.purge(retention_days='-1')
    inventory_indices = session.query(InventoryIndex).all()
    self.assertEqual(3, len(inventory_indices))
    resources = session.query(Inventory).all()
    self.assertEqual(6, len(resources))