path: root/common/prque/lazyqueue_test.go

// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package prque

import (
    "math/rand"
    "sync"
    "testing"
    "time"

    "github.com/ethereum/go-ethereum/common/mclock"
)

const (
    testItems        = 1000
    testPriorityStep = 100
    testSteps        = 1000000
    testStepPeriod   = time.Millisecond
    testQueueRefresh = time.Second
    testAvgRate      = float64(testPriorityStep) / float64(testItems) / float64(testStepPeriod)
)

type lazyItem struct {
    p, maxp int64
    last    mclock.AbsTime
    index   int
}

func testPriority(a interface{}, now mclock.AbsTime) int64 {
    return a.(*lazyItem).p
}

func testMaxPriority(a interface{}, until mclock.AbsTime) int64 {
    i := a.(*lazyItem)
    dt := until - i.last
    i.maxp = i.p + int64(float64(dt)*testAvgRate)
    return i.maxp
}

func testSetIndex(a interface{}, i int) {
    a.(*lazyItem).index = i
}

func TestLazyQueue(t *testing.T) {
    rand.Seed(time.Now().UnixNano())
    clock := &mclock.Simulated{}
    q := NewLazyQueue(testSetIndex, testPriority, testMaxPriority, clock, testQueueRefresh)

    var (
        items  [testItems]lazyItem
        maxPri int64
    )

    for i := range items[:] {
        items[i].p = rand.Int63n(testPriorityStep * 10)
        if items[i].p > maxPri {
            maxPri = items[i].p
        }
        items[i].index = -1
        q.Push(&items[i])
    }

    var lock sync.Mutex
    stopCh := make(chan chan struct{})
    go func() {
        for {
            select {
            case <-clock.After(testQueueRefresh):
                lock.Lock()
                q.Refresh()
                lock.Unlock()
            case stop := <-stopCh:
                close(stop)
                return
            }
        }
    }()

    for c := 0; c < testSteps; c++ {
        i := rand.Intn(testItems)
        lock.Lock()
        items[i].p += rand.Int63n(testPriorityStep*2-1) + 1
        if items[i].p > maxPri {
            maxPri = items[i].p
        }
        items[i].last = clock.Now()
        if items[i].p > items[i].maxp {
            q.Update(items[i].index)
        }
        if rand.Intn(100) == 0 {
            p := q.PopItem().(*lazyItem)
            if p.p != maxPri {
                t.Fatalf("incorrect item (best known priority %d, popped %d)", maxPri, p.p)
            }
            q.Push(p)
        }
        lock.Unlock()
        clock.Run(testStepPeriod)
        clock.WaitForTimers(1)
    }

    stop := make(chan struct{})
    stopCh <- stop
    <-stop
}