code: func (c *testCluster) AddNode(n *testNode) error {
  	c.counter++
  	if err := c.runNode(n, c.counter); err != nil {
  		c.counter--
  		return err
  	}
  	c.nodes[n.node.NodeID()] = n
  	c.nodesOrder[n.node.NodeID()] = c.counter
  	return nil
  }
docs: // AddNode adds a new node to the cluster