function TestPlan.visualize(l)local Q={}l:visitAllNodes(function(l,x)table.insert(Q,(" "):rep(3*x)..l.phrase)end)return table.concat(Q,"\n")end

function TestPlan:visualize()
	local buffer = {}
	self:visitAllNodes(function(node, level)
		table.insert(buffer, (" "):rep(3 * level) .. node.phrase)
	end)
	return table.concat(buffer, "\n")
end
