path: root/core/consensus-timestamp_test.go

// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core 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 dexon-consensus-core 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 dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.

package core

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

    "github.com/stretchr/testify/suite"

    "github.com/dexon-foundation/dexon-consensus-core/common"
    "github.com/dexon-foundation/dexon-consensus-core/core/types"
)

type ConsensusTimestampTest struct {
    suite.Suite
}

func (s *ConsensusTimestampTest) generateBlocksWithTimestamp(
    blockNum, chainNum int,
    step, sigma time.Duration) []*types.Block {
    blocks := make([]*types.Block, blockNum)
    chainIDs := make([]uint32, len(blocks))
    for i := range chainIDs {
        chainIDs[i] = uint32(i % chainNum)
    }
    rand.Shuffle(len(chainIDs), func(i, j int) {
        chainIDs[i], chainIDs[j] = chainIDs[j], chainIDs[i]
    })
    chainTimestamps := make(map[uint32]time.Time)
    for idx := range blocks {
        blocks[idx] = &types.Block{}
        block := blocks[idx]
        if idx < chainNum {
            // Genesis blocks.
            block.Position.ChainID = uint32(idx)
            block.ParentHash = common.Hash{}
            block.Position.Height = 0
            s.Require().True(block.IsGenesis())
            chainTimestamps[uint32(idx)] = time.Now().UTC()
        } else {
            block.Position.ChainID = chainIDs[idx]
            // Assign 1 to height to make this block non-genesis.
            block.Position.Height = 1
            s.Require().False(block.IsGenesis())
        }
        block.Timestamp = chainTimestamps[block.Position.ChainID]
        // Update timestamp for next block.
        diffSeconds := rand.NormFloat64() * sigma.Seconds()
        diffSeconds = math.Min(diffSeconds, step.Seconds()/2.1)
        diffSeconds = math.Max(diffSeconds, -step.Seconds()/2.1)
        diffDuration := time.Duration(diffSeconds*1000) * time.Millisecond
        chainTimestamps[block.Position.ChainID] =
            chainTimestamps[block.Position.ChainID].Add(step).Add(diffDuration)
        s.Require().True(block.Timestamp.Before(
            chainTimestamps[block.Position.ChainID]))
    }
    return blocks
}

func (s *ConsensusTimestampTest) extractTimestamps(
    blocks []*types.Block) []time.Time {
    timestamps := make([]time.Time, 0, len(blocks))
    for _, block := range blocks {
        if block.IsGenesis() {
            continue
        }
        timestamps = append(timestamps, block.Finalization.Timestamp)
    }
    return timestamps
}

// TestTimestampPartition verifies that processing segments of compatction chain
// should have the same result as processing the whole chain at once.
func (s *ConsensusTimestampTest) TestTimestampPartition() {
    blockNums := []int{50, 100, 30}
    chainNum := 19
    sigma := 100 * time.Millisecond
    totalTimestamps := make([]time.Time, 0)
    ct := newConsensusTimestamp(time.Time{}, uint32(chainNum))
    totalBlockNum := 0
    for _, blockNum := range blockNums {
        totalBlockNum += blockNum
    }
    totalChain := s.generateBlocksWithTimestamp(
        totalBlockNum, chainNum, time.Second, sigma)
    for _, blockNum := range blockNums {
        var chain []*types.Block
        chain, totalChain = totalChain[:blockNum], totalChain[blockNum:]
        err := ct.processBlocks(chain)
        s.Require().NoError(err)
        timestamps := s.extractTimestamps(chain)
        totalChain = append(totalChain, chain...)
        totalTimestamps = append(totalTimestamps, timestamps...)
    }
    ct2 := newConsensusTimestamp(time.Time{}, uint32(chainNum))
    err := ct2.processBlocks(totalChain)
    s.Require().NoError(err)
    timestamps2 := s.extractTimestamps(totalChain)
    s.Equal(totalTimestamps, timestamps2)
}

func (s *ConsensusTimestampTest) TestTimestampIncrease() {
    chainNum := 19
    sigma := 100 * time.Millisecond
    ct := newConsensusTimestamp(time.Time{}, uint32(chainNum))
    chain := s.generateBlocksWithTimestamp(1000, chainNum, time.Second, sigma)
    err := ct.processBlocks(chain)
    s.Require().NoError(err)
    timestamps := s.extractTimestamps(chain)
    for i := 1; i < len(timestamps); i++ {
        s.False(timestamps[i].Before(timestamps[i-1]))
    }
    // Test if the processBlocks is stable.
    ct2 := newConsensusTimestamp(time.Time{}, uint32(chainNum))
    ct2.processBlocks(chain)
    s.Require().NoError(err)
    timestamps2 := s.extractTimestamps(chain)
    s.Equal(timestamps, timestamps2)
}

func TestConsensusTimestamp(t *testing.T) {
    suite.Run(t, new(ConsensusTimestampTest))
}