test: clone types.Config, test.Governance, test.State (#262)

6 files changed, 608 insertions, 42 deletions

diff --git a/core/test/governance.go b/core/test/governance.go
index a3b9168..4a2b61d 100644
--- a/core/test/governance.go
+++ b/core/test/governance.go
@@ -18,29 +18,25 @@
 package test
 
 import (
-	"fmt"
+	"encoding/hex"
+	"reflect"
+	"sort"
 	"sync"
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/ecdsa"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
 	typesDKG "github.com/dexon-foundation/dexon-consensus-core/core/types/dkg"
 )
 
-var (
-	// ErrPrivateKeyNotExists means caller request private key for an
-	// unknown node ID.
-	ErrPrivateKeyNotExists = fmt.Errorf("private key not exists")
-)
-
 // Governance is an implementation of Goverance for testing purpose.
 type Governance struct {
-	privateKeys map[types.NodeID]crypto.PrivateKey
-	configs     []*types.Config
-	nodeSets    [][]crypto.PublicKey
-	state       *State
-	lock        sync.RWMutex
+	configs  []*types.Config
+	nodeSets [][]crypto.PublicKey
+	state    *State
+	lock     sync.RWMutex
 }
 
 // NewGovernance constructs a Governance instance.
@@ -193,3 +189,74 @@ func (g *Governance) CatchUpWithRound(round uint64) {
 		g.nodeSets = append(g.nodeSets, nodeSet)
 	}
 }
+
+// Clone a governance instance with replicate internal state.
+func (g *Governance) Clone() *Governance {
+	g.lock.RLock()
+	defer g.lock.RUnlock()
+	// Clone state.
+	copiedState := g.state.Clone()
+	// Clone configs.
+	copiedConfigs := []*types.Config{}
+	for _, c := range g.configs {
+		copiedConfigs = append(copiedConfigs, c.Clone())
+	}
+	// Clone node sets.
+	// NOTE: here I assume the key is from ecdsa.
+	copiedNodeSets := [][]crypto.PublicKey{}
+	for _, nodeSetForRound := range g.nodeSets {
+		copiedNodeSet := []crypto.PublicKey{}
+		for _, node := range nodeSetForRound {
+			pubKey, err := ecdsa.NewPublicKeyFromByteSlice(node.Bytes())
+			if err != nil {
+				panic(err)
+			}
+			copiedNodeSet = append(copiedNodeSet, pubKey)
+		}
+		copiedNodeSets = append(copiedNodeSets, copiedNodeSet)
+	}
+	return &Governance{
+		configs:  copiedConfigs,
+		state:    copiedState,
+		nodeSets: copiedNodeSets,
+	}
+}
+
+// Equal checks equality between two Governance instances.
+func (g *Governance) Equal(other *Governance, checkState bool) bool {
+	// Check configs.
+	if !reflect.DeepEqual(g.configs, other.configs) {
+		return false
+	}
+	// Check node sets.
+	if len(g.nodeSets) != len(other.nodeSets) {
+		return false
+	}
+	getSortedKeys := func(keys []crypto.PublicKey) (encoded []string) {
+		for _, key := range keys {
+			encoded = append(encoded, hex.EncodeToString(key.Bytes()))
+		}
+		sort.Strings(encoded)
+		return
+	}
+	for round, nodeSetsForRound := range g.nodeSets {
+		otherNodeSetsForRound := other.nodeSets[round]
+		if len(nodeSetsForRound) != len(otherNodeSetsForRound) {
+			return false
+		}
+		if !reflect.DeepEqual(
+			getSortedKeys(nodeSetsForRound),
+			getSortedKeys(otherNodeSetsForRound)) {
+			return false
+		}
+	}
+	// Check state if needed.
+	//
+	// While testing, it's expected that two governance instances contain
+	// different state, only the snapshots (configs and node sets) are
+	// essentially equal.
+	if checkState {
+		return g.state.Equal(other.state) == nil
+	}
+	return true
+}
diff --git a/core/test/governance_test.go b/core/test/governance_test.go
new file mode 100644
index 0000000..16de2a1
--- /dev/null
+++ b/core/test/governance_test.go
@@ -0,0 +1,64 @@
+// 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 test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type GovernanceTestSuite struct {
+	suite.Suite
+}
+
+func (s *GovernanceTestSuite) TestEqual() {
+	var req = s.Require()
+	// Setup a base governance.
+	_, genesisNodes, err := NewKeys(20)
+	req.NoError(err)
+	g1, err := NewGovernance(genesisNodes, 100*time.Millisecond)
+	req.NoError(err)
+	// Create a governance with different lambda.
+	g2, err := NewGovernance(genesisNodes, 50*time.Millisecond)
+	req.NoError(err)
+	req.False(g1.Equal(g2, true))
+	// Create configs for 3 rounds for g1.
+	g1.CatchUpWithRound(3)
+	// Make a clone.
+	g3 := g1.Clone()
+	req.True(g1.Equal(g3, true))
+	// Create a new round for g1.
+	g1.CatchUpWithRound(4)
+	req.False(g1.Equal(g3, true))
+	// Make another clone.
+	g4 := g1.Clone()
+	req.True(g1.Equal(g4, true))
+	// Add a node to g4.
+	_, newNodes, err := NewKeys(1)
+	req.NoError(err)
+	g4.State().RequestChange(StateAddNode, newNodes[0])
+	g1.CatchUpWithRound(5)
+	g4.CatchUpWithRound(5)
+	req.False(g1.Equal(g4, true))
+}
+
+func TestGovernance(t *testing.T) {
+	suite.Run(t, new(GovernanceTestSuite))
+}
diff --git a/core/test/state.go b/core/test/state.go
index f8f9ebe..34c38bc 100644
--- a/core/test/state.go
+++ b/core/test/state.go
@@ -18,8 +18,10 @@
 package test
 
 import (
+	"bytes"
 	"errors"
 	"math"
+	"reflect"
 	"sync"
 	"time"
 
@@ -46,6 +48,28 @@ var (
 	ErrUnknownStateChangeType = errors.New("unknown state change type")
 	// ErrProposerIsFinal means a proposer of one complaint is finalized.
 	ErrProposerIsFinal = errors.New("proposer is final")
+	// ErrStateConfigNotEqual means configuration part of two states is not
+	// equal.
+	ErrStateConfigNotEqual = errors.New("config not equal")
+	// ErrStateLocalFlagNotEqual means local flag of two states is not equal.
+	ErrStateLocalFlagNotEqual = errors.New("local flag not equal")
+	// ErrStateNodeSetNotEqual means node sets of two states are not equal.
+	ErrStateNodeSetNotEqual = errors.New("node set not equal")
+	// ErrStateDKGComplaintsNotEqual means DKG complaints for two states are not
+	// equal.
+	ErrStateDKGComplaintsNotEqual = errors.New("dkg complaints not equal")
+	// ErrStateDKGMasterPublicKeysNotEqual means DKG master public keys of two
+	// states are not equal.
+	ErrStateDKGMasterPublicKeysNotEqual = errors.New(
+		"dkg master public keys not equal")
+	// ErrStateDKGFinalsNotEqual means DKG finalizations of two states are not
+	// equal.
+	ErrStateDKGFinalsNotEqual = errors.New("dkg finalizations not equal")
+	// ErrStateCRSsNotEqual means CRSs of two states are not equal.
+	ErrStateCRSsNotEqual = errors.New("crs not equal")
+	// ErrStatePendingChangesNotEqual means pending change requests of two
+	// states are not equal.
+	ErrStatePendingChangesNotEqual = errors.New("pending changes not equal")
 )
 
 // Types of state change.
@@ -247,6 +271,288 @@ func (s *State) unpackPayload(
 	return
 }
 
+func (s *State) cloneDKGComplaint(
+	comp *typesDKG.Complaint) (copied *typesDKG.Complaint) {
+	b, err := rlp.EncodeToBytes(comp)
+	if err != nil {
+		panic(err)
+	}
+	copied = &typesDKG.Complaint{}
+	if err = rlp.DecodeBytes(b, copied); err != nil {
+		panic(err)
+	}
+	return
+}
+
+func (s *State) cloneDKGMasterPublicKey(mpk *typesDKG.MasterPublicKey) (
+	copied *typesDKG.MasterPublicKey) {
+	b, err := rlp.EncodeToBytes(mpk)
+	if err != nil {
+		panic(err)
+	}
+	copied = typesDKG.NewMasterPublicKey()
+	if err = rlp.DecodeBytes(b, copied); err != nil {
+		panic(err)
+	}
+	return
+}
+
+func (s *State) cloneDKGFinalize(final *typesDKG.Finalize) (
+	copied *typesDKG.Finalize) {
+	b, err := rlp.EncodeToBytes(final)
+	if err != nil {
+		panic(err)
+	}
+	copied = &typesDKG.Finalize{}
+	if err = rlp.DecodeBytes(b, copied); err != nil {
+		panic(err)
+	}
+	return
+}
+
+// Equal checks equality between State instance.
+func (s *State) Equal(other *State) error {
+	// Check configuration part.
+	configEqual := s.numChains == other.numChains &&
+		s.lambdaBA == other.lambdaBA &&
+		s.lambdaDKG == other.lambdaDKG &&
+		s.k == other.k &&
+		s.phiRatio == other.phiRatio &&
+		s.notarySetSize == other.notarySetSize &&
+		s.dkgSetSize == other.dkgSetSize &&
+		s.roundInterval == other.roundInterval &&
+		s.minBlockInterval == other.minBlockInterval &&
+		s.maxBlockInterval == other.maxBlockInterval
+	if !configEqual {
+		return ErrStateConfigNotEqual
+	}
+	// Check local flag.
+	if s.local != other.local {
+		return ErrStateLocalFlagNotEqual
+	}
+	// Check node set.
+	if len(s.nodes) != len(other.nodes) {
+		return ErrStateNodeSetNotEqual
+	}
+	for nID, key := range s.nodes {
+		otherKey, exists := other.nodes[nID]
+		if !exists {
+			return ErrStateNodeSetNotEqual
+		}
+		if bytes.Compare(key.Bytes(), otherKey.Bytes()) != 0 {
+			return ErrStateNodeSetNotEqual
+		}
+	}
+	// Check DKG Complaints, here I assume the addition sequence of complaints
+	// proposed by one node would be identical on each node (this should be true
+	// when state change requests are carried by blocks and executed in order).
+	if len(s.dkgComplaints) != len(other.dkgComplaints) {
+		return ErrStateDKGComplaintsNotEqual
+	}
+	for round, compsForRound := range s.dkgComplaints {
+		otherCompsForRound, exists := other.dkgComplaints[round]
+		if !exists {
+			return ErrStateDKGComplaintsNotEqual
+		}
+		if len(compsForRound) != len(otherCompsForRound) {
+			return ErrStateDKGComplaintsNotEqual
+		}
+		for nID, comps := range compsForRound {
+			otherComps, exists := otherCompsForRound[nID]
+			if !exists {
+				return ErrStateDKGComplaintsNotEqual
+			}
+			if len(comps) != len(otherComps) {
+				return ErrStateDKGComplaintsNotEqual
+			}
+			for idx, comp := range comps {
+				if !comp.Equal(otherComps[idx]) {
+					return ErrStateDKGComplaintsNotEqual
+				}
+			}
+		}
+	}
+	// Check DKG master public keys.
+	if len(s.dkgMasterPublicKeys) != len(other.dkgMasterPublicKeys) {
+		return ErrStateDKGMasterPublicKeysNotEqual
+	}
+	for round, mKeysForRound := range s.dkgMasterPublicKeys {
+		otherMKeysForRound, exists := other.dkgMasterPublicKeys[round]
+		if !exists {
+			return ErrStateDKGMasterPublicKeysNotEqual
+		}
+		if len(mKeysForRound) != len(otherMKeysForRound) {
+			return ErrStateDKGMasterPublicKeysNotEqual
+		}
+		for nID, mKey := range mKeysForRound {
+			otherMKey, exists := otherMKeysForRound[nID]
+			if !exists {
+				return ErrStateDKGMasterPublicKeysNotEqual
+			}
+			if !mKey.Equal(otherMKey) {
+				return ErrStateDKGMasterPublicKeysNotEqual
+			}
+		}
+	}
+	// Check DKG finals.
+	if len(s.dkgFinals) != len(other.dkgFinals) {
+		return ErrStateDKGFinalsNotEqual
+	}
+	for round, finalsForRound := range s.dkgFinals {
+		otherFinalsForRound, exists := other.dkgFinals[round]
+		if !exists {
+			return ErrStateDKGFinalsNotEqual
+		}
+		if len(finalsForRound) != len(otherFinalsForRound) {
+			return ErrStateDKGFinalsNotEqual
+		}
+		for nID, final := range finalsForRound {
+			otherFinal, exists := otherFinalsForRound[nID]
+			if !exists {
+				return ErrStateDKGFinalsNotEqual
+			}
+			if !final.Equal(otherFinal) {
+				return ErrStateDKGFinalsNotEqual
+			}
+		}
+	}
+	// Check CRS part.
+	if len(s.crs) != len(other.crs) {
+		return ErrStateCRSsNotEqual
+	}
+	for idx, crs := range s.crs {
+		if crs != other.crs[idx] {
+			return ErrStateCRSsNotEqual
+		}
+	}
+	// Check pending changes.
+	if !reflect.DeepEqual(
+		s.pendingChangedConfigs, other.pendingChangedConfigs) {
+		return ErrStatePendingChangesNotEqual
+	}
+	if !reflect.DeepEqual(s.pendingCRS, other.pendingCRS) {
+		return ErrStatePendingChangesNotEqual
+	}
+	if !reflect.DeepEqual(s.pendingNodes, other.pendingNodes) {
+		return ErrStatePendingChangesNotEqual
+	}
+	// Check pending DKG complaints.
+	if len(s.pendingDKGComplaints) != len(other.pendingDKGComplaints) {
+		return ErrStatePendingChangesNotEqual
+	}
+	for idx, comp := range s.pendingDKGComplaints {
+		if !comp.Equal(other.pendingDKGComplaints[idx]) {
+			return ErrStatePendingChangesNotEqual
+		}
+	}
+	// Check pending DKG finals.
+	if len(s.pendingDKGFinals) != len(other.pendingDKGFinals) {
+		return ErrStatePendingChangesNotEqual
+	}
+	for idx, final := range s.pendingDKGFinals {
+		if !final.Equal(other.pendingDKGFinals[idx]) {
+			return ErrStatePendingChangesNotEqual
+		}
+	}
+	// Check pending DKG Master public keys.
+	if len(s.pendingDKGMasterPublicKeys) !=
+		len(other.pendingDKGMasterPublicKeys) {
+		return ErrStatePendingChangesNotEqual
+	}
+	for idx, mKey := range s.pendingDKGMasterPublicKeys {
+		if !mKey.Equal(other.pendingDKGMasterPublicKeys[idx]) {
+			return ErrStatePendingChangesNotEqual
+		}
+	}
+	return nil
+}
+
+// Clone returns a copied State instance.
+func (s *State) Clone() (copied *State) {
+	// Clone configuration parts.
+	copied = &State{
+		numChains:        s.numChains,
+		lambdaBA:         s.lambdaBA,
+		lambdaDKG:        s.lambdaDKG,
+		k:                s.k,
+		phiRatio:         s.phiRatio,
+		notarySetSize:    s.notarySetSize,
+		dkgSetSize:       s.dkgSetSize,
+		roundInterval:    s.roundInterval,
+		minBlockInterval: s.minBlockInterval,
+		maxBlockInterval: s.maxBlockInterval,
+		local:            s.local,
+		nodes:            make(map[types.NodeID]crypto.PublicKey),
+		dkgComplaints: make(
+			map[uint64]map[types.NodeID][]*typesDKG.Complaint),
+		dkgMasterPublicKeys: make(
+			map[uint64]map[types.NodeID]*typesDKG.MasterPublicKey),
+		dkgFinals:             make(map[uint64]map[types.NodeID]*typesDKG.Finalize),
+		pendingChangedConfigs: make(map[StateChangeType]interface{}),
+	}
+	// Nodes
+	for nID, key := range s.nodes {
+		copied.nodes[nID] = key
+	}
+	// DKG & CRS
+	for round, complaintsForRound := range s.dkgComplaints {
+		copied.dkgComplaints[round] =
+			make(map[types.NodeID][]*typesDKG.Complaint)
+		for nID, comps := range complaintsForRound {
+			tmpComps := []*typesDKG.Complaint{}
+			for _, comp := range comps {
+				tmpComps = append(tmpComps, s.cloneDKGComplaint(comp))
+			}
+			copied.dkgComplaints[round][nID] = tmpComps
+		}
+	}
+	for round, mKeysForRound := range s.dkgMasterPublicKeys {
+		copied.dkgMasterPublicKeys[round] =
+			make(map[types.NodeID]*typesDKG.MasterPublicKey)
+		for nID, mKey := range mKeysForRound {
+			copied.dkgMasterPublicKeys[round][nID] =
+				s.cloneDKGMasterPublicKey(mKey)
+		}
+	}
+	for round, finalsForRound := range s.dkgFinals {
+		copied.dkgFinals[round] = make(map[types.NodeID]*typesDKG.Finalize)
+		for nID, final := range finalsForRound {
+			copied.dkgFinals[round][nID] = s.cloneDKGFinalize(final)
+		}
+	}
+	for _, crs := range s.crs {
+		copied.crs = append(copied.crs, crs)
+	}
+	// Pending Changes
+	for t, v := range s.pendingChangedConfigs {
+		copied.pendingChangedConfigs[t] = v
+	}
+	for _, bs := range s.pendingNodes {
+		tmpBytes := make([]byte, len(bs))
+		copy(tmpBytes, bs)
+		copied.pendingNodes = append(copied.pendingNodes, tmpBytes)
+	}
+	for _, comp := range s.pendingDKGComplaints {
+		copied.pendingDKGComplaints = append(
+			copied.pendingDKGComplaints, s.cloneDKGComplaint(comp))
+	}
+	for _, final := range s.pendingDKGFinals {
+		copied.pendingDKGFinals = append(
+			copied.pendingDKGFinals, s.cloneDKGFinalize(final))
+	}
+	for _, mKey := range s.pendingDKGMasterPublicKeys {
+		copied.pendingDKGMasterPublicKeys = append(
+			copied.pendingDKGMasterPublicKeys, s.cloneDKGMasterPublicKey(mKey))
+	}
+	for _, req := range s.pendingCRS {
+		copied.pendingCRS = append(copied.pendingCRS, &crsAdditionRequest{
+			Round: req.Round,
+			CRS:   req.CRS,
+		})
+	}
+	return
+}
+
 // Apply change requests, this function would also
 // be called when we extract these request from delivered blocks.
 func (s *State) Apply(reqsAsBytes []byte) (err error) {
@@ -527,15 +833,7 @@ func (s *State) DKGComplaints(round uint64) []*typesDKG.Complaint {
 	tmpComps := make([]*typesDKG.Complaint, 0, len(comps))
 	for _, compProp := range comps {
 		for _, comp := range compProp {
-			bytes, err := rlp.EncodeToBytes(comp)
-			if err != nil {
-				panic(err)
-			}
-			compCopy := &typesDKG.Complaint{}
-			if err = rlp.DecodeBytes(bytes, compCopy); err != nil {
-				panic(err)
-			}
-			tmpComps = append(tmpComps, compCopy)
+			tmpComps = append(tmpComps, s.cloneDKGComplaint(comp))
 		}
 	}
 	return tmpComps
@@ -553,16 +851,7 @@ func (s *State) DKGMasterPublicKeys(round uint64) []*typesDKG.MasterPublicKey {
 	}
 	mpks := make([]*typesDKG.MasterPublicKey, 0, len(masterPublicKeys))
 	for _, mpk := range masterPublicKeys {
-		// Return a deep copied master public keys.
-		b, err := rlp.EncodeToBytes(mpk)
-		if err != nil {
-			panic(err)
-		}
-		mpkCopy := typesDKG.NewMasterPublicKey()
-		if err = rlp.DecodeBytes(b, mpkCopy); err != nil {
-			panic(err)
-		}
-		mpks = append(mpks, mpkCopy)
+		mpks = append(mpks, s.cloneDKGMasterPublicKey(mpk))
 	}
 	return mpks
 }
diff --git a/core/test/state_test.go b/core/test/state_test.go
index ebb5a25..59b8f63 100644
--- a/core/test/state_test.go
+++ b/core/test/state_test.go
@@ -82,15 +82,6 @@ func (s *StateTestSuite) newDKGFinal(round uint64) *typesDKG.Finalize {
 	}
 }
 
-func (s *StateTestSuite) genNodes(count int) (nodes []crypto.PublicKey) {
-	for i := 0; i < count; i++ {
-		prv, err := ecdsa.NewPrivateKey()
-		s.Require().NoError(err)
-		nodes = append(nodes, prv.PublicKey())
-	}
-	return
-}
-
 func (s *StateTestSuite) compareNodes(node1, node2 []crypto.PublicKey) bool {
 	id1 := common.Hashes{}
 	for _, n := range node1 {
@@ -162,13 +153,103 @@ func (s *StateTestSuite) checkConfigChanges(config *types.Config) {
 	req.Equal(config.DKGSetSize, uint32(6))
 }
 
+func (s *StateTestSuite) TestEqual() {
+	var (
+		req    = s.Require()
+		lambda = 250 * time.Millisecond
+	)
+	_, genesisNodes, err := NewKeys(20)
+	req.NoError(err)
+	st := NewState(genesisNodes, lambda, true)
+	req.NoError(st.Equal(st))
+	// One node is missing.
+	st1 := NewState(genesisNodes, lambda, true)
+	for nID := range st1.nodes {
+		delete(st1.nodes, nID)
+		break
+	}
+	req.Equal(st.Equal(st1), ErrStateNodeSetNotEqual)
+	// Make some changes.
+	st2 := st.Clone()
+	req.NoError(st.Equal(st2))
+	s.makeConfigChanges(st)
+	req.Equal(st.Equal(st2), ErrStateConfigNotEqual)
+	crs := common.NewRandomHash()
+	req.NoError(st.ProposeCRS(1, crs))
+	masterPubKey := s.newDKGMasterPublicKey(2)
+	comp := s.newDKGComplaint(2)
+	final := s.newDKGFinal(2)
+	s.makeDKGChanges(st, masterPubKey, comp, final)
+	// Remove dkg complaints from cloned one to check if equal.
+	st3 := st.Clone()
+	req.NoError(st.Equal(st3))
+	delete(st3.dkgComplaints, uint64(2))
+	req.Equal(st.Equal(st3), ErrStateDKGComplaintsNotEqual)
+	// Remove dkg master public key from cloned one to check if equal.
+	st4 := st.Clone()
+	req.NoError(st.Equal(st4))
+	delete(st4.dkgMasterPublicKeys, uint64(2))
+	req.Equal(st.Equal(st4), ErrStateDKGMasterPublicKeysNotEqual)
+	// Remove dkg finalize from cloned one to check if equal.
+	st5 := st.Clone()
+	req.NoError(st.Equal(st5))
+	delete(st5.dkgFinals, uint64(2))
+	req.Equal(st.Equal(st5), ErrStateDKGFinalsNotEqual)
+}
+
+func (s *StateTestSuite) TestPendingChangesEqual() {
+	var (
+		req    = s.Require()
+		lambda = 250 * time.Millisecond
+	)
+	// Setup a non-local mode State instance.
+	_, genesisNodes, err := NewKeys(20)
+	req.NoError(err)
+	st := NewState(genesisNodes, lambda, false)
+	req.NoError(st.Equal(st))
+	// Apply some changes.
+	s.makeConfigChanges(st)
+	crs := common.NewRandomHash()
+	req.NoError(st.ProposeCRS(1, crs))
+	masterPubKey := s.newDKGMasterPublicKey(2)
+	comp := s.newDKGComplaint(2)
+	final := s.newDKGFinal(2)
+	s.makeDKGChanges(st, masterPubKey, comp, final)
+	// Remove pending config changes.
+	st1 := st.Clone()
+	req.NoError(st.Equal(st1))
+	st1.pendingChangedConfigs = make(map[StateChangeType]interface{})
+	req.Equal(st.Equal(st1), ErrStatePendingChangesNotEqual)
+	// Remove pending crs changes.
+	st2 := st.Clone()
+	req.NoError(st.Equal(st2))
+	st2.pendingCRS = []*crsAdditionRequest{}
+	req.Equal(st.Equal(st2), ErrStatePendingChangesNotEqual)
+	// Remove pending dkg complaints changes.
+	st3 := st.Clone()
+	req.NoError(st.Equal(st3))
+	st3.pendingDKGComplaints = []*typesDKG.Complaint{}
+	req.Equal(st.Equal(st3), ErrStatePendingChangesNotEqual)
+	// Remove pending dkg master public key changes.
+	st4 := st.Clone()
+	req.NoError(st.Equal(st4))
+	st4.pendingDKGMasterPublicKeys = []*typesDKG.MasterPublicKey{}
+	req.Equal(st.Equal(st4), ErrStatePendingChangesNotEqual)
+	// Remove pending dkg finalize changes.
+	st5 := st.Clone()
+	req.NoError(st.Equal(st5))
+	st5.pendingDKGFinals = []*typesDKG.Finalize{}
+	req.Equal(st.Equal(st5), ErrStatePendingChangesNotEqual)
+}
+
 func (s *StateTestSuite) TestLocalMode() {
 	// Test State with local mode.
 	var (
 		req    = s.Require()
 		lambda = 250 * time.Millisecond
 	)
-	genesisNodes := s.genNodes(20)
+	_, genesisNodes, err := NewKeys(20)
+	req.NoError(err)
 	st := NewState(genesisNodes, lambda, true)
 	config1, nodes1 := st.Snapshot()
 	req.True(s.compareNodes(genesisNodes, nodes1))
@@ -228,7 +309,8 @@ func (s *StateTestSuite) TestPacking() {
 		lambda = 250 * time.Millisecond
 	)
 	// Make config changes.
-	genesisNodes := s.genNodes(20)
+	_, genesisNodes, err := NewKeys(20)
+	req.NoError(err)
 	st := NewState(genesisNodes, lambda, false)
 	s.makeConfigChanges(st)
 	// Add new CRS.
diff --git a/core/types/config.go b/core/types/config.go
index 372ffb4..df28b20 100644
--- a/core/types/config.go
+++ b/core/types/config.go
@@ -46,6 +46,22 @@ type Config struct {
 	MaxBlockInterval time.Duration
 }
 
+// Clone return a copied configuration.
+func (c *Config) Clone() *Config {
+	return &Config{
+		NumChains:        c.NumChains,
+		LambdaBA:         c.LambdaBA,
+		LambdaDKG:        c.LambdaDKG,
+		K:                c.K,
+		PhiRatio:         c.PhiRatio,
+		NotarySetSize:    c.NotarySetSize,
+		DKGSetSize:       c.DKGSetSize,
+		RoundInterval:    c.RoundInterval,
+		MinBlockInterval: c.MinBlockInterval,
+		MaxBlockInterval: c.MaxBlockInterval,
+	}
+}
+
 // Bytes returns []byte representation of Config.
 func (c *Config) Bytes() []byte {
 	binaryNumChains := make([]byte, 4)
diff --git a/core/types/config_test.go b/core/types/config_test.go
new file mode 100644
index 0000000..7bf8134
--- /dev/null
+++ b/core/types/config_test.go
@@ -0,0 +1,48 @@
+// 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 types
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+)
+
+type ConfigTestSuite struct {
+	suite.Suite
+}
+
+func (s *ConfigTestSuite) TestClone() {
+	c := &Config{
+		NumChains:        2,
+		LambdaBA:         1 * time.Millisecond,
+		LambdaDKG:        2 * time.Hour,
+		K:                4,
+		NotarySetSize:    5,
+		DKGSetSize:       6,
+		RoundInterval:    3 * time.Second,
+		MinBlockInterval: 7 * time.Nanosecond,
+		MaxBlockInterval: 9 * time.Minute,
+	}
+	s.Require().Equal(c, c.Clone())
+}
+
+func TestConfig(t *testing.T) {
+	suite.Run(t, new(ConfigTestSuite))
+}