func (test *snapshotTest) checkEqual(state, checkstate *StateDB) error {
	for _, addr := range test.addrs {
		var err error
		checkeq := func(op string, a, b interface{}) bool {
			if err == nil && !reflect.DeepEqual(a, b) {
				err = fmt.Errorf("got %s(%s) == %v, want %v", op, addr.Hex(), a, b)
				return false
			}
			return true
		}
		checkeq("Exist", state.Exist(addr), checkstate.Exist(addr))
		checkeq("HasSuicided", state.HasSuicided(addr), checkstate.HasSuicided(addr))
		checkeq("GetBalance", state.GetBalance(addr), checkstate.GetBalance(addr))
		checkeq("GetNonce", state.GetNonce(addr), checkstate.GetNonce(addr))
		checkeq("GetCode", state.GetCode(addr), checkstate.GetCode(addr))
		checkeq("GetCodeHash", state.GetCodeHash(addr), checkstate.GetCodeHash(addr))
		checkeq("GetCodeSize", state.GetCodeSize(addr), checkstate.GetCodeSize(addr))
		if obj := state.getStateObject(addr); obj != nil {
			state.ForEachStorage(addr, func(key, value common.Hash) bool {
				return checkeq("GetState("+key.Hex()+")", checkstate.GetState(addr, key), value)
			})
			checkstate.ForEachStorage(addr, func(key, value common.Hash) bool {
				return checkeq("GetState("+key.Hex()+")", checkstate.GetState(addr, key), value)
			})
		}
		if err != nil {
			return err
		}
	}
	if state.GetRefund() != checkstate.GetRefund() {
		return fmt.Errorf("got GetRefund() == %d, want GetRefund() == %d",
			state.GetRefund(), checkstate.GetRefund())
	}
	if !reflect.DeepEqual(state.GetLogs(common.Hash{}), checkstate.GetLogs(common.Hash{})) {
		return fmt.Errorf("got GetLogs(common.Hash{}) == %v, want GetLogs(common.Hash{}) == %v",
			state.GetLogs(common.Hash{}), checkstate.GetLogs(common.Hash{}))
	}
	return nil
}
checkEqual checks that methods of state and checkstate return the same values.
package state
import (
	"bytes"
	"encoding/binary"
	"fmt"
	"math"
	"math/big"
	"math/rand"
	"reflect"
	"strings"
	"testing"
	"testing/quick"
	check "gopkg.in/check.v1"
	"github.com/dappledger/AnnChain/eth/common"
	"github.com/dappledger/AnnChain/eth/core/types"
	"github.com/dappledger/AnnChain/eth/ethdb"
)
func TestUpdateLeaks(t *testing.T) {
	db := ethdb.NewMemDatabase()
	state, _ := New(common.Hash{}, NewDatabase(db))
	for i := byte(0); i < 255; i++ {
		addr := common.BytesToAddress([]byte{i})
		state.AddBalance(addr, big.NewInt(int64(11*i)))
		state.SetNonce(addr, uint64(42*i))
		if i%2 == 0 {
			state.SetState(addr, common.BytesToHash([]byte{i, i, i}), common.BytesToHash([]byte{i, i, i, i}))
		}
		if i%3 == 0 {
			state.SetCode(addr, []byte{i, i, i, i, i})
		}
		state.IntermediateRoot(false)
	}
	for _, key := range db.Keys() {
		value, _ := db.Get(key)
		t.Errorf("State leaked into database: %x -> %x", key, value)
	}
}
func TestIntermediateLeaks(t *testing.T) {
	transDb := ethdb.NewMemDatabase()
	finalDb := ethdb.NewMemDatabase()
	transState, _ := New(common.Hash{}, NewDatabase(transDb))
	finalState, _ := New(common.Hash{}, NewDatabase(finalDb))
	modify := func(state *StateDB, addr common.Address, i, tweak byte) {
		state.SetBalance(addr, big.NewInt(int64(11*i)+int64(tweak)))
		state.SetNonce(addr, uint64(42*i+tweak))
		if i%2 == 0 {
			state.SetState(addr, common.Hash{i, i, i, 0}, common.Hash{})
			state.SetState(addr, common.Hash{i, i, i, tweak}, common.Hash{i, i, i, i, tweak})
		}
		if i%3 == 0 {
			state.SetCode(addr, []byte{i, i, i, i, i, tweak})
		}
	}
	for i := byte(0); i < 255; i++ {
		modify(transState, common.Address{byte(i)}, i, 0)
	}
	transState.IntermediateRoot(false)
	for i := byte(0); i < 255; i++ {
		modify(transState, common.Address{byte(i)}, i, 99)
		modify(finalState, common.Address{byte(i)}, i, 99)
	}
	if _, err := transState.Commit(false); err != nil {
		t.Fatalf("failed to commit transition state: %v", err)
	}
	if _, err := finalState.Commit(false); err != nil {
		t.Fatalf("failed to commit final state: %v", err)
	}
	for _, key := range finalDb.Keys() {
		if _, err := transDb.Get(key); err != nil {
			val, _ := finalDb.Get(key)
			t.Errorf("entry missing from the transition database: %x -> %x", key, val)
		}
	}
	for _, key := range transDb.Keys() {
		if _, err := finalDb.Get(key); err != nil {
			val, _ := transDb.Get(key)
			t.Errorf("extra entry in the transition database: %x -> %x", key, val)
		}
	}
}
func TestCopy(t *testing.T) {
	orig, _ := New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
	for i := byte(0); i < 255; i++ {
		obj := orig.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
		obj.AddBalance(big.NewInt(int64(i)))
		orig.updateStateObject(obj)
	}
	orig.Finalise(false)
	copy := orig.Copy()
	for i := byte(0); i < 255; i++ {
		origObj := orig.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
		copyObj := copy.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
		origObj.AddBalance(big.NewInt(2 * int64(i)))
		copyObj.AddBalance(big.NewInt(3 * int64(i)))
		orig.updateStateObject(origObj)
		copy.updateStateObject(copyObj)
	}
	done := make(chan struct{})
	go func() {
		orig.Finalise(true)
		close(done)
	}()
	copy.Finalise(true)
	<-done
	for i := byte(0); i < 255; i++ {
		origObj := orig.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
		copyObj := copy.GetOrNewStateObject(common.BytesToAddress([]byte{i}))
		if want := big.NewInt(3 * int64(i)); origObj.Balance().Cmp(want) != 0 {
			t.Errorf("orig obj %d: balance mismatch: have %v, want %v", i, origObj.Balance(), want)
		}
		if want := big.NewInt(4 * int64(i)); copyObj.Balance().Cmp(want) != 0 {
			t.Errorf("copy obj %d: balance mismatch: have %v, want %v", i, copyObj.Balance(), want)
		}
	}
}
func TestSnapshotRandom(t *testing.T) {
	config := &quick.Config{MaxCount: 1000}
	err := quick.Check((*snapshotTest).run, config)
	if cerr, ok := err.(*quick.CheckError); ok {
		test := cerr.In[0].(*snapshotTest)
		t.Errorf("%v:\n%s", test.err, test)
	} else if err != nil {
		t.Error(err)
	}
}
type snapshotTest struct {
	addrs     []common.Address  
	actions   []testAction      
	snapshots []int             
	err       error             
}
type testAction struct {
	name   string
	fn     func(testAction, *StateDB)
	args   []int64
	noAddr bool
}
func newTestAction(addr common.Address, r *rand.Rand) testAction {
	actions := []testAction{
		{
			name: "SetBalance",
			fn: func(a testAction, s *StateDB) {
				s.SetBalance(addr, big.NewInt(a.args[0]))
			},
			args: make([]int64, 1),
		},
		{
			name: "AddBalance",
			fn: func(a testAction, s *StateDB) {
				s.AddBalance(addr, big.NewInt(a.args[0]))
			},
			args: make([]int64, 1),
		},
		{
			name: "SetNonce",
			fn: func(a testAction, s *StateDB) {
				s.SetNonce(addr, uint64(a.args[0]))
			},
			args: make([]int64, 1),
		},
		{
			name: "SetState",
			fn: func(a testAction, s *StateDB) {
				var key, val common.Hash
				binary.BigEndian.PutUint16(key[:], uint16(a.args[0]))
				binary.BigEndian.PutUint16(val[:], uint16(a.args[1]))
				s.SetState(addr, key, val)
			},
			args: make([]int64, 2),
		},
		{
			name: "SetCode",
			fn: func(a testAction, s *StateDB) {
				code := make([]byte, 16)
				binary.BigEndian.PutUint64(code, uint64(a.args[0]))
				binary.BigEndian.PutUint64(code[8:], uint64(a.args[1]))
				s.SetCode(addr, code)
			},
			args: make([]int64, 2),
		},
		{
			name: "CreateAccount",
			fn: func(a testAction, s *StateDB) {
				s.CreateAccount(addr)
			},
		},
		{
			name: "Suicide",
			fn: func(a testAction, s *StateDB) {
				s.Suicide(addr)
			},
		},
		{
			name: "AddRefund",
			fn: func(a testAction, s *StateDB) {
				s.AddRefund(uint64(a.args[0]))
			},
			args:   make([]int64, 1),
			noAddr: true,
		},
		{
			name: "AddLog",
			fn: func(a testAction, s *StateDB) {
				data := make([]byte, 2)
				binary.BigEndian.PutUint16(data, uint16(a.args[0]))
				s.AddLog(&types.Log{Address: addr, Data: data})
			},
			args: make([]int64, 1),
		},
	}
	action := actions[r.Intn(len(actions))]
	var nameargs []string
	if !action.noAddr {
		nameargs = append(nameargs, addr.Hex())
	}
	for _, i := range action.args {
		action.args[i] = rand.Int63n(100)
		nameargs = append(nameargs, fmt.Sprint(action.args[i]))
	}
	action.name += strings.Join(nameargs, ", ")
	return action
}
func (*snapshotTest) Generate(r *rand.Rand, size int) reflect.Value {
	addrs := make([]common.Address, 50)
	for i := range addrs {
		addrs[i][0] = byte(i)
	}
	actions := make([]testAction, size)
	for i := range actions {
		addr := addrs[r.Intn(len(addrs))]
		actions[i] = newTestAction(addr, r)
	}
	nsnapshots := int(math.Sqrt(float64(size)))
	if size > 0 && nsnapshots == 0 {
		nsnapshots = 1
	}
	snapshots := make([]int, nsnapshots)
	snaplen := len(actions) / nsnapshots
	for i := range snapshots {
		snapshots[i] = (i * snaplen) + r.Intn(snaplen)
	}
	return reflect.ValueOf(&snapshotTest{addrs, actions, snapshots, nil})
}
func (test *snapshotTest) String() string {
	out := new(bytes.Buffer)
	sindex := 0
	for i, action := range test.actions {
		if len(test.snapshots) > sindex && i == test.snapshots[sindex] {
			fmt.Fprintf(out, "---- snapshot %d ----\n", sindex)
			sindex++
		}
		fmt.Fprintf(out, "%4d: %s\n", i, action.name)
	}
	return out.String()
}
func (test *snapshotTest) run() bool {
	var (
		state, _     = New(common.Hash{}, NewDatabase(ethdb.NewMemDatabase()))
		snapshotRevs = make([]int, len(test.snapshots))
		sindex       = 0
	)
	for i, action := range test.actions {
		if len(test.snapshots) > sindex && i == test.snapshots[sindex] {
			snapshotRevs[sindex] = state.Snapshot()
			sindex++
		}
		action.fn(action, state)
	}
	for sindex--; sindex >= 0; sindex-- {
		checkstate, _ := New(common.Hash{}, state.Database())
		for _, action := range test.actions[:test.snapshots[sindex]] {
			action.fn(action, checkstate)
		}
		state.RevertToSnapshot(snapshotRevs[sindex])
		if err := test.checkEqual(state, checkstate); err != nil {
			test.err = fmt.Errorf("state mismatch after revert to snapshot %d\n%v", sindex, err)
			return false
		}
	}
	return true
}