def METHOD_NAME(self):
    refer_layer_orders = ['node1', 'node2', 'node3', 'node4']
    refer_nodes = ['node1']
    self.assertEqual(order.median_value(refer_nodes, refer_layer_orders), 0)
    refer_nodes = ['node1', 'node4']
    self.assertEqual(order.median_value(refer_nodes, refer_layer_orders), 1.5)
    refer_nodes = ['node1', 'node4', 'node2']
    self.assertEqual(order.median_value(refer_nodes, refer_layer_orders), 1)