github.com/anthdm/go-ethereum@v1.8.4-0.20180412101906-60516c83b011/p2p/discv5/topic_test.go (about)

     1  // Copyright 2016 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package discv5
    18  
    19  import (
    20  	"encoding/binary"
    21  	"testing"
    22  	"time"
    23  
    24  	"github.com/ethereum/go-ethereum/common"
    25  	"github.com/ethereum/go-ethereum/common/mclock"
    26  )
    27  
    28  func TestTopicRadius(t *testing.T) {
    29  	now := mclock.Now()
    30  	topic := Topic("qwerty")
    31  	rad := newTopicRadius(topic)
    32  	targetRad := (^uint64(0)) / 100
    33  
    34  	waitFn := func(addr common.Hash) time.Duration {
    35  		prefix := binary.BigEndian.Uint64(addr[0:8])
    36  		dist := prefix ^ rad.topicHashPrefix
    37  		relDist := float64(dist) / float64(targetRad)
    38  		relTime := (1 - relDist/2) * 2
    39  		if relTime < 0 {
    40  			relTime = 0
    41  		}
    42  		return time.Duration(float64(targetWaitTime) * relTime)
    43  	}
    44  
    45  	bcnt := 0
    46  	cnt := 0
    47  	var sum float64
    48  	for cnt < 100 {
    49  		addr := rad.nextTarget(false).target
    50  		wait := waitFn(addr)
    51  		ticket := &ticket{
    52  			topics:  []Topic{topic},
    53  			regTime: []mclock.AbsTime{mclock.AbsTime(wait)},
    54  			node:    &Node{nodeNetGuts: nodeNetGuts{sha: addr}},
    55  		}
    56  		rad.adjustWithTicket(now, addr, ticketRef{ticket, 0})
    57  		if rad.radius != maxRadius {
    58  			cnt++
    59  			sum += float64(rad.radius)
    60  		} else {
    61  			bcnt++
    62  			if bcnt > 500 {
    63  				t.Errorf("Radius did not converge in 500 iterations")
    64  			}
    65  		}
    66  	}
    67  	avgRel := sum / float64(cnt) / float64(targetRad)
    68  	if avgRel > 1.05 || avgRel < 0.95 {
    69  		t.Errorf("Average/target ratio is too far from 1 (%v)", avgRel)
    70  	}
    71  }