path: root/core/tx_pool_test.go

// Copyright 2015 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 core

import (
    "crypto/ecdsa"
    "fmt"
    "io/ioutil"
    "math/big"
    "math/rand"
    "os"
    "testing"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/state"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/event"
    "github.com/ethereum/go-ethereum/params"
)

// testTxPoolConfig is a transaction pool configuration without stateful disk
// sideeffects used during testing.
var testTxPoolConfig TxPoolConfig

func init() {
    testTxPoolConfig = DefaultTxPoolConfig
    testTxPoolConfig.Journal = ""
}

type testBlockChain struct {
    statedb       *state.StateDB
    gasLimit      uint64
    chainHeadFeed *event.Feed
}

func (bc *testBlockChain) CurrentBlock() *types.Block {
    return types.NewBlock(&types.Header{
        GasLimit: bc.gasLimit,
    }, nil, nil, nil)
}

func (bc *testBlockChain) GetBlock(hash common.Hash, number uint64) *types.Block {
    return bc.CurrentBlock()
}

func (bc *testBlockChain) StateAt(common.Hash) (*state.StateDB, error) {
    return bc.statedb, nil
}

func (bc *testBlockChain) SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) event.Subscription {
    return bc.chainHeadFeed.Subscribe(ch)
}

func transaction(nonce uint64, gaslimit uint64, key *ecdsa.PrivateKey) *types.Transaction {
    return pricedTransaction(nonce, gaslimit, big.NewInt(1), key)
}

func pricedTransaction(nonce uint64, gaslimit uint64, gasprice *big.Int, key *ecdsa.PrivateKey) *types.Transaction {
    tx, _ := types.SignTx(types.NewTransaction(nonce, common.Address{}, big.NewInt(100), gaslimit, gasprice, nil), types.HomesteadSigner{}, key)
    return tx
}

func setupTxPool() (*TxPool, *ecdsa.PrivateKey) {
    diskdb, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(diskdb))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    key, _ := crypto.GenerateKey()
    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)

    return pool, key
}

// validateTxPoolInternals checks various consistency invariants within the pool.
func validateTxPoolInternals(pool *TxPool) error {
    pool.mu.RLock()
    defer pool.mu.RUnlock()

    // Ensure the total transaction set is consistent with pending + queued
    pending, queued := pool.stats()
    if total := len(pool.all); total != pending+queued {
        return fmt.Errorf("total transaction count %d != %d pending + %d queued", total, pending, queued)
    }
    if priced := pool.priced.items.Len() - pool.priced.stales; priced != pending+queued {
        return fmt.Errorf("total priced transaction count %d != %d pending + %d queued", priced, pending, queued)
    }
    // Ensure the next nonce to assign is the correct one
    for addr, txs := range pool.pending {
        // Find the last transaction
        var last uint64
        for nonce := range txs.txs.items {
            if last < nonce {
                last = nonce
            }
        }
        if nonce := pool.pendingState.GetNonce(addr); nonce != last+1 {
            return fmt.Errorf("pending nonce mismatch: have %v, want %v", nonce, last+1)
        }
    }
    return nil
}

// validateEvents checks that the correct number of transaction addition events
// were fired on the pool's event feed.
func validateEvents(events chan TxPreEvent, count int) error {
    for i := 0; i < count; i++ {
        select {
        case <-events:
        case <-time.After(time.Second):
            return fmt.Errorf("event #%d not fired", i)
        }
    }
    select {
    case tx := <-events:
        return fmt.Errorf("more than %d events fired: %v", count, tx.Tx)

    case <-time.After(50 * time.Millisecond):
        // This branch should be "default", but it's a data race between goroutines,
        // reading the event channel and pushng into it, so better wait a bit ensuring
        // really nothing gets injected.
    }
    return nil
}

func deriveSender(tx *types.Transaction) (common.Address, error) {
    return types.Sender(types.HomesteadSigner{}, tx)
}

type testChain struct {
    *testBlockChain
    address common.Address
    trigger *bool
}

// testChain.State() is used multiple times to reset the pending state.
// when simulate is true it will create a state that indicates
// that tx0 and tx1 are included in the chain.
func (c *testChain) State() (*state.StateDB, error) {
    // delay "state change" by one. The tx pool fetches the
    // state multiple times and by delaying it a bit we simulate
    // a state change between those fetches.
    stdb := c.statedb
    if *c.trigger {
        db, _ := ethdb.NewMemDatabase()
        c.statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
        // simulate that the new head block included tx0 and tx1
        c.statedb.SetNonce(c.address, 2)
        c.statedb.SetBalance(c.address, new(big.Int).SetUint64(params.Ether))
        *c.trigger = false
    }
    return stdb, nil
}

// This test simulates a scenario where a new block is imported during a
// state reset and tests whether the pending state is in sync with the
// block head event that initiated the resetState().
func TestStateChangeDuringTransactionPoolReset(t *testing.T) {
    t.Parallel()

    var (
        db, _      = ethdb.NewMemDatabase()
        key, _     = crypto.GenerateKey()
        address    = crypto.PubkeyToAddress(key.PublicKey)
        statedb, _ = state.New(common.Hash{}, state.NewDatabase(db))
        trigger    = false
    )

    // setup pool with 2 transaction in it
    statedb.SetBalance(address, new(big.Int).SetUint64(params.Ether))
    blockchain := &testChain{&testBlockChain{statedb, 1000000000, new(event.Feed)}, address, &trigger}

    tx0 := transaction(0, 100000, key)
    tx1 := transaction(1, 100000, key)

    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
    defer pool.Stop()

    nonce := pool.State().GetNonce(address)
    if nonce != 0 {
        t.Fatalf("Invalid nonce, want 0, got %d", nonce)
    }

    pool.AddRemotes(types.Transactions{tx0, tx1})

    nonce = pool.State().GetNonce(address)
    if nonce != 2 {
        t.Fatalf("Invalid nonce, want 2, got %d", nonce)
    }

    // trigger state change in the background
    trigger = true

    pool.lockedReset(nil, nil)

    _, err := pool.Pending()
    if err != nil {
        t.Fatalf("Could not fetch pending transactions: %v", err)
    }
    nonce = pool.State().GetNonce(address)
    if nonce != 2 {
        t.Fatalf("Invalid nonce, want 2, got %d", nonce)
    }
}

func TestInvalidTransactions(t *testing.T) {
    t.Parallel()

    pool, key := setupTxPool()
    defer pool.Stop()

    tx := transaction(0, 100, key)
    from, _ := deriveSender(tx)

    pool.currentState.AddBalance(from, big.NewInt(1))
    if err := pool.AddRemote(tx); err != ErrInsufficientFunds {
        t.Error("expected", ErrInsufficientFunds)
    }

    balance := new(big.Int).Add(tx.Value(), new(big.Int).Mul(new(big.Int).SetUint64(tx.Gas()), tx.GasPrice()))
    pool.currentState.AddBalance(from, balance)
    if err := pool.AddRemote(tx); err != ErrIntrinsicGas {
        t.Error("expected", ErrIntrinsicGas, "got", err)
    }

    pool.currentState.SetNonce(from, 1)
    pool.currentState.AddBalance(from, big.NewInt(0xffffffffffffff))
    tx = transaction(0, 100000, key)
    if err := pool.AddRemote(tx); err != ErrNonceTooLow {
        t.Error("expected", ErrNonceTooLow)
    }

    tx = transaction(1, 100000, key)
    pool.gasPrice = big.NewInt(1000)
    if err := pool.AddRemote(tx); err != ErrUnderpriced {
        t.Error("expected", ErrUnderpriced, "got", err)
    }
    if err := pool.AddLocal(tx); err != nil {
        t.Error("expected", nil, "got", err)
    }
}

func TestTransactionQueue(t *testing.T) {
    t.Parallel()

    pool, key := setupTxPool()
    defer pool.Stop()

    tx := transaction(0, 100, key)
    from, _ := deriveSender(tx)
    pool.currentState.AddBalance(from, big.NewInt(1000))
    pool.lockedReset(nil, nil)
    pool.enqueueTx(tx.Hash(), tx)

    pool.promoteExecutables([]common.Address{from})
    if len(pool.pending) != 1 {
        t.Error("expected valid txs to be 1 is", len(pool.pending))
    }

    tx = transaction(1, 100, key)
    from, _ = deriveSender(tx)
    pool.currentState.SetNonce(from, 2)
    pool.enqueueTx(tx.Hash(), tx)
    pool.promoteExecutables([]common.Address{from})
    if _, ok := pool.pending[from].txs.items[tx.Nonce()]; ok {
        t.Error("expected transaction to be in tx pool")
    }

    if len(pool.queue) > 0 {
        t.Error("expected transaction queue to be empty. is", len(pool.queue))
    }

    pool, key = setupTxPool()
    defer pool.Stop()

    tx1 := transaction(0, 100, key)
    tx2 := transaction(10, 100, key)
    tx3 := transaction(11, 100, key)
    from, _ = deriveSender(tx1)
    pool.currentState.AddBalance(from, big.NewInt(1000))
    pool.lockedReset(nil, nil)

    pool.enqueueTx(tx1.Hash(), tx1)
    pool.enqueueTx(tx2.Hash(), tx2)
    pool.enqueueTx(tx3.Hash(), tx3)

    pool.promoteExecutables([]common.Address{from})

    if len(pool.pending) != 1 {
        t.Error("expected tx pool to be 1, got", len(pool.pending))
    }
    if pool.queue[from].Len() != 2 {
        t.Error("expected len(queue) == 2, got", pool.queue[from].Len())
    }
}

func TestTransactionNegativeValue(t *testing.T) {
    t.Parallel()

    pool, key := setupTxPool()
    defer pool.Stop()

    tx, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(-1), 100, big.NewInt(1), nil), types.HomesteadSigner{}, key)
    from, _ := deriveSender(tx)
    pool.currentState.AddBalance(from, big.NewInt(1))
    if err := pool.AddRemote(tx); err != ErrNegativeValue {
        t.Error("expected", ErrNegativeValue, "got", err)
    }
}

func TestTransactionChainFork(t *testing.T) {
    t.Parallel()

    pool, key := setupTxPool()
    defer pool.Stop()

    addr := crypto.PubkeyToAddress(key.PublicKey)
    resetState := func() {
        db, _ := ethdb.NewMemDatabase()
        statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
        statedb.AddBalance(addr, big.NewInt(100000000000000))

        pool.chain = &testBlockChain{statedb, 1000000, new(event.Feed)}
        pool.lockedReset(nil, nil)
    }
    resetState()

    tx := transaction(0, 100000, key)
    if _, err := pool.add(tx, false); err != nil {
        t.Error("didn't expect error", err)
    }
    pool.removeTx(tx.Hash(), true)

    // reset the pool's internal state
    resetState()
    if _, err := pool.add(tx, false); err != nil {
        t.Error("didn't expect error", err)
    }
}

func TestTransactionDoubleNonce(t *testing.T) {
    t.Parallel()

    pool, key := setupTxPool()
    defer pool.Stop()

    addr := crypto.PubkeyToAddress(key.PublicKey)
    resetState := func() {
        db, _ := ethdb.NewMemDatabase()
        statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
        statedb.AddBalance(addr, big.NewInt(100000000000000))

        pool.chain = &testBlockChain{statedb, 1000000, new(event.Feed)}
        pool.lockedReset(nil, nil)
    }
    resetState()

    signer := types.HomesteadSigner{}
    tx1, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 100000, big.NewInt(1), nil), signer, key)
    tx2, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 1000000, big.NewInt(2), nil), signer, key)
    tx3, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 1000000, big.NewInt(1), nil), signer, key)

    // Add the first two transaction, ensure higher priced stays only
    if replace, err := pool.add(tx1, false); err != nil || replace {
        t.Errorf("first transaction insert failed (%v) or reported replacement (%v)", err, replace)
    }
    if replace, err := pool.add(tx2, false); err != nil || !replace {
        t.Errorf("second transaction insert failed (%v) or not reported replacement (%v)", err, replace)
    }
    pool.promoteExecutables([]common.Address{addr})
    if pool.pending[addr].Len() != 1 {
        t.Error("expected 1 pending transactions, got", pool.pending[addr].Len())
    }
    if tx := pool.pending[addr].txs.items[0]; tx.Hash() != tx2.Hash() {
        t.Errorf("transaction mismatch: have %x, want %x", tx.Hash(), tx2.Hash())
    }
    // Add the third transaction and ensure it's not saved (smaller price)
    pool.add(tx3, false)
    pool.promoteExecutables([]common.Address{addr})
    if pool.pending[addr].Len() != 1 {
        t.Error("expected 1 pending transactions, got", pool.pending[addr].Len())
    }
    if tx := pool.pending[addr].txs.items[0]; tx.Hash() != tx2.Hash() {
        t.Errorf("transaction mismatch: have %x, want %x", tx.Hash(), tx2.Hash())
    }
    // Ensure the total transaction count is correct
    if len(pool.all) != 1 {
        t.Error("expected 1 total transactions, got", len(pool.all))
    }
}

func TestTransactionMissingNonce(t *testing.T) {
    t.Parallel()

    pool, key := setupTxPool()
    defer pool.Stop()

    addr := crypto.PubkeyToAddress(key.PublicKey)
    pool.currentState.AddBalance(addr, big.NewInt(100000000000000))
    tx := transaction(1, 100000, key)
    if _, err := pool.add(tx, false); err != nil {
        t.Error("didn't expect error", err)
    }
    if len(pool.pending) != 0 {
        t.Error("expected 0 pending transactions, got", len(pool.pending))
    }
    if pool.queue[addr].Len() != 1 {
        t.Error("expected 1 queued transaction, got", pool.queue[addr].Len())
    }
    if len(pool.all) != 1 {
        t.Error("expected 1 total transactions, got", len(pool.all))
    }
}

func TestTransactionNonceRecovery(t *testing.T) {
    t.Parallel()

    const n = 10
    pool, key := setupTxPool()
    defer pool.Stop()

    addr := crypto.PubkeyToAddress(key.PublicKey)
    pool.currentState.SetNonce(addr, n)
    pool.currentState.AddBalance(addr, big.NewInt(100000000000000))
    pool.lockedReset(nil, nil)

    tx := transaction(n, 100000, key)
    if err := pool.AddRemote(tx); err != nil {
        t.Error(err)
    }
    // simulate some weird re-order of transactions and missing nonce(s)
    pool.currentState.SetNonce(addr, n-1)
    pool.lockedReset(nil, nil)
    if fn := pool.pendingState.GetNonce(addr); fn != n-1 {
        t.Errorf("expected nonce to be %d, got %d", n-1, fn)
    }
}

// Tests that if an account runs out of funds, any pending and queued transactions
// are dropped.
func TestTransactionDropping(t *testing.T) {
    t.Parallel()

    // Create a test account and fund it
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000))

    // Add some pending and some queued transactions
    var (
        tx0  = transaction(0, 100, key)
        tx1  = transaction(1, 200, key)
        tx2  = transaction(2, 300, key)
        tx10 = transaction(10, 100, key)
        tx11 = transaction(11, 200, key)
        tx12 = transaction(12, 300, key)
    )
    pool.promoteTx(account, tx0.Hash(), tx0)
    pool.promoteTx(account, tx1.Hash(), tx1)
    pool.promoteTx(account, tx2.Hash(), tx2)
    pool.enqueueTx(tx10.Hash(), tx10)
    pool.enqueueTx(tx11.Hash(), tx11)
    pool.enqueueTx(tx12.Hash(), tx12)

    // Check that pre and post validations leave the pool as is
    if pool.pending[account].Len() != 3 {
        t.Errorf("pending transaction mismatch: have %d, want %d", pool.pending[account].Len(), 3)
    }
    if pool.queue[account].Len() != 3 {
        t.Errorf("queued transaction mismatch: have %d, want %d", pool.queue[account].Len(), 3)
    }
    if len(pool.all) != 6 {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 6)
    }
    pool.lockedReset(nil, nil)
    if pool.pending[account].Len() != 3 {
        t.Errorf("pending transaction mismatch: have %d, want %d", pool.pending[account].Len(), 3)
    }
    if pool.queue[account].Len() != 3 {
        t.Errorf("queued transaction mismatch: have %d, want %d", pool.queue[account].Len(), 3)
    }
    if len(pool.all) != 6 {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 6)
    }
    // Reduce the balance of the account, and check that invalidated transactions are dropped
    pool.currentState.AddBalance(account, big.NewInt(-650))
    pool.lockedReset(nil, nil)

    if _, ok := pool.pending[account].txs.items[tx0.Nonce()]; !ok {
        t.Errorf("funded pending transaction missing: %v", tx0)
    }
    if _, ok := pool.pending[account].txs.items[tx1.Nonce()]; !ok {
        t.Errorf("funded pending transaction missing: %v", tx0)
    }
    if _, ok := pool.pending[account].txs.items[tx2.Nonce()]; ok {
        t.Errorf("out-of-fund pending transaction present: %v", tx1)
    }
    if _, ok := pool.queue[account].txs.items[tx10.Nonce()]; !ok {
        t.Errorf("funded queued transaction missing: %v", tx10)
    }
    if _, ok := pool.queue[account].txs.items[tx11.Nonce()]; !ok {
        t.Errorf("funded queued transaction missing: %v", tx10)
    }
    if _, ok := pool.queue[account].txs.items[tx12.Nonce()]; ok {
        t.Errorf("out-of-fund queued transaction present: %v", tx11)
    }
    if len(pool.all) != 4 {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 4)
    }
    // Reduce the block gas limit, check that invalidated transactions are dropped
    pool.chain.(*testBlockChain).gasLimit = 100
    pool.lockedReset(nil, nil)

    if _, ok := pool.pending[account].txs.items[tx0.Nonce()]; !ok {
        t.Errorf("funded pending transaction missing: %v", tx0)
    }
    if _, ok := pool.pending[account].txs.items[tx1.Nonce()]; ok {
        t.Errorf("over-gased pending transaction present: %v", tx1)
    }
    if _, ok := pool.queue[account].txs.items[tx10.Nonce()]; !ok {
        t.Errorf("funded queued transaction missing: %v", tx10)
    }
    if _, ok := pool.queue[account].txs.items[tx11.Nonce()]; ok {
        t.Errorf("over-gased queued transaction present: %v", tx11)
    }
    if len(pool.all) != 2 {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 2)
    }
}

// Tests that if a transaction is dropped from the current pending pool (e.g. out
// of fund), all consecutive (still valid, but not executable) transactions are
// postponed back into the future queue to prevent broadcasting them.
func TestTransactionPostponing(t *testing.T) {
    t.Parallel()

    // Create the pool to test the postponing with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create two test accounts to produce different gap profiles with
    keys := make([]*ecdsa.PrivateKey, 2)
    accs := make([]common.Address, len(keys))

    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        accs[i] = crypto.PubkeyToAddress(keys[i].PublicKey)

        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(50100))
    }
    // Add a batch consecutive pending transactions for validation
    txs := []*types.Transaction{}
    for i, key := range keys {

        for j := 0; j < 100; j++ {
            var tx *types.Transaction
            if (i+j)%2 == 0 {
                tx = transaction(uint64(j), 25000, key)
            } else {
                tx = transaction(uint64(j), 50000, key)
            }
            txs = append(txs, tx)
        }
    }
    for i, err := range pool.AddRemotes(txs) {
        if err != nil {
            t.Fatalf("tx %d: failed to add transactions: %v", i, err)
        }
    }
    // Check that pre and post validations leave the pool as is
    if pending := pool.pending[accs[0]].Len() + pool.pending[accs[1]].Len(); pending != len(txs) {
        t.Errorf("pending transaction mismatch: have %d, want %d", pending, len(txs))
    }
    if len(pool.queue) != 0 {
        t.Errorf("queued accounts mismatch: have %d, want %d", len(pool.queue), 0)
    }
    if len(pool.all) != len(txs) {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), len(txs))
    }
    pool.lockedReset(nil, nil)
    if pending := pool.pending[accs[0]].Len() + pool.pending[accs[1]].Len(); pending != len(txs) {
        t.Errorf("pending transaction mismatch: have %d, want %d", pending, len(txs))
    }
    if len(pool.queue) != 0 {
        t.Errorf("queued accounts mismatch: have %d, want %d", len(pool.queue), 0)
    }
    if len(pool.all) != len(txs) {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), len(txs))
    }
    // Reduce the balance of the account, and check that transactions are reorganised
    for _, addr := range accs {
        pool.currentState.AddBalance(addr, big.NewInt(-1))
    }
    pool.lockedReset(nil, nil)

    // The first account's first transaction remains valid, check that subsequent
    // ones are either filtered out, or queued up for later.
    if _, ok := pool.pending[accs[0]].txs.items[txs[0].Nonce()]; !ok {
        t.Errorf("tx %d: valid and funded transaction missing from pending pool: %v", 0, txs[0])
    }
    if _, ok := pool.queue[accs[0]].txs.items[txs[0].Nonce()]; ok {
        t.Errorf("tx %d: valid and funded transaction present in future queue: %v", 0, txs[0])
    }
    for i, tx := range txs[1:100] {
        if i%2 == 1 {
            if _, ok := pool.pending[accs[0]].txs.items[tx.Nonce()]; ok {
                t.Errorf("tx %d: valid but future transaction present in pending pool: %v", i+1, tx)
            }
            if _, ok := pool.queue[accs[0]].txs.items[tx.Nonce()]; !ok {
                t.Errorf("tx %d: valid but future transaction missing from future queue: %v", i+1, tx)
            }
        } else {
            if _, ok := pool.pending[accs[0]].txs.items[tx.Nonce()]; ok {
                t.Errorf("tx %d: out-of-fund transaction present in pending pool: %v", i+1, tx)
            }
            if _, ok := pool.queue[accs[0]].txs.items[tx.Nonce()]; ok {
                t.Errorf("tx %d: out-of-fund transaction present in future queue: %v", i+1, tx)
            }
        }
    }
    // The second account's first transaction got invalid, check that all transactions
    // are either filtered out, or queued up for later.
    if pool.pending[accs[1]] != nil {
        t.Errorf("invalidated account still has pending transactions")
    }
    for i, tx := range txs[100:] {
        if i%2 == 1 {
            if _, ok := pool.queue[accs[1]].txs.items[tx.Nonce()]; !ok {
                t.Errorf("tx %d: valid but future transaction missing from future queue: %v", 100+i, tx)
            }
        } else {
            if _, ok := pool.queue[accs[1]].txs.items[tx.Nonce()]; ok {
                t.Errorf("tx %d: out-of-fund transaction present in future queue: %v", 100+i, tx)
            }
        }
    }
    if len(pool.all) != len(txs)/2 {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), len(txs)/2)
    }
}

// Tests that if the transaction pool has both executable and non-executable
// transactions from an origin account, filling the nonce gap moves all queued
// ones into the pending pool.
func TestTransactionGapFilling(t *testing.T) {
    t.Parallel()

    // Create a test account and fund it
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    // Keep track of transaction events to ensure all executables get announced
    events := make(chan TxPreEvent, testTxPoolConfig.AccountQueue+5)
    sub := pool.txFeed.Subscribe(events)
    defer sub.Unsubscribe()

    // Create a pending and a queued transaction with a nonce-gap in between
    if err := pool.AddRemote(transaction(0, 100000, key)); err != nil {
        t.Fatalf("failed to add pending transaction: %v", err)
    }
    if err := pool.AddRemote(transaction(2, 100000, key)); err != nil {
        t.Fatalf("failed to add queued transaction: %v", err)
    }
    pending, queued := pool.Stats()
    if pending != 1 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 1)
    }
    if queued != 1 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 1)
    }
    if err := validateEvents(events, 1); err != nil {
        t.Fatalf("original event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Fill the nonce gap and ensure all transactions become pending
    if err := pool.AddRemote(transaction(1, 100000, key)); err != nil {
        t.Fatalf("failed to add gapped transaction: %v", err)
    }
    pending, queued = pool.Stats()
    if pending != 3 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 3)
    }
    if queued != 0 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
    }
    if err := validateEvents(events, 2); err != nil {
        t.Fatalf("gap-filling event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that if the transaction count belonging to a single account goes above
// some threshold, the higher transactions are dropped to prevent DOS attacks.
func TestTransactionQueueAccountLimiting(t *testing.T) {
    t.Parallel()

    // Create a test account and fund it
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    // Keep queuing up transactions and make sure all above a limit are dropped
    for i := uint64(1); i <= testTxPoolConfig.AccountQueue+5; i++ {
        if err := pool.AddRemote(transaction(i, 100000, key)); err != nil {
            t.Fatalf("tx %d: failed to add transaction: %v", i, err)
        }
        if len(pool.pending) != 0 {
            t.Errorf("tx %d: pending pool size mismatch: have %d, want %d", i, len(pool.pending), 0)
        }
        if i <= testTxPoolConfig.AccountQueue {
            if pool.queue[account].Len() != int(i) {
                t.Errorf("tx %d: queue size mismatch: have %d, want %d", i, pool.queue[account].Len(), i)
            }
        } else {
            if pool.queue[account].Len() != int(testTxPoolConfig.AccountQueue) {
                t.Errorf("tx %d: queue limit mismatch: have %d, want %d", i, pool.queue[account].Len(), testTxPoolConfig.AccountQueue)
            }
        }
    }
    if len(pool.all) != int(testTxPoolConfig.AccountQueue) {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), testTxPoolConfig.AccountQueue)
    }
}

// Tests that if the transaction count belonging to multiple accounts go above
// some threshold, the higher transactions are dropped to prevent DOS attacks.
//
// This logic should not hold for local transactions, unless the local tracking
// mechanism is disabled.
func TestTransactionQueueGlobalLimiting(t *testing.T) {
    testTransactionQueueGlobalLimiting(t, false)
}
func TestTransactionQueueGlobalLimitingNoLocals(t *testing.T) {
    testTransactionQueueGlobalLimiting(t, true)
}

func testTransactionQueueGlobalLimiting(t *testing.T, nolocals bool) {
    t.Parallel()

    // Create the pool to test the limit enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.NoLocals = nolocals
    config.GlobalQueue = config.AccountQueue*3 - 1 // reduce the queue limits to shorten test time (-1 to make it non divisible)

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create a number of test accounts and fund them (last one will be the local)
    keys := make([]*ecdsa.PrivateKey, 5)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    local := keys[len(keys)-1]

    // Generate and queue a batch of transactions
    nonces := make(map[common.Address]uint64)

    txs := make(types.Transactions, 0, 3*config.GlobalQueue)
    for len(txs) < cap(txs) {
        key := keys[rand.Intn(len(keys)-1)] // skip adding transactions with the local account
        addr := crypto.PubkeyToAddress(key.PublicKey)

        txs = append(txs, transaction(nonces[addr]+1, 100000, key))
        nonces[addr]++
    }
    // Import the batch and verify that limits have been enforced
    pool.AddRemotes(txs)

    queued := 0
    for addr, list := range pool.queue {
        if list.Len() > int(config.AccountQueue) {
            t.Errorf("addr %x: queued accounts overflown allowance: %d > %d", addr, list.Len(), config.AccountQueue)
        }
        queued += list.Len()
    }
    if queued > int(config.GlobalQueue) {
        t.Fatalf("total transactions overflow allowance: %d > %d", queued, config.GlobalQueue)
    }
    // Generate a batch of transactions from the local account and import them
    txs = txs[:0]
    for i := uint64(0); i < 3*config.GlobalQueue; i++ {
        txs = append(txs, transaction(i+1, 100000, local))
    }
    pool.AddLocals(txs)

    // If locals are disabled, the previous eviction algorithm should apply here too
    if nolocals {
        queued := 0
        for addr, list := range pool.queue {
            if list.Len() > int(config.AccountQueue) {
                t.Errorf("addr %x: queued accounts overflown allowance: %d > %d", addr, list.Len(), config.AccountQueue)
            }
            queued += list.Len()
        }
        if queued > int(config.GlobalQueue) {
            t.Fatalf("total transactions overflow allowance: %d > %d", queued, config.GlobalQueue)
        }
    } else {
        // Local exemptions are enabled, make sure the local account owned the queue
        if len(pool.queue) != 1 {
            t.Errorf("multiple accounts in queue: have %v, want %v", len(pool.queue), 1)
        }
        // Also ensure no local transactions are ever dropped, even if above global limits
        if queued := pool.queue[crypto.PubkeyToAddress(local.PublicKey)].Len(); uint64(queued) != 3*config.GlobalQueue {
            t.Fatalf("local account queued transaction count mismatch: have %v, want %v", queued, 3*config.GlobalQueue)
        }
    }
}

// Tests that if an account remains idle for a prolonged amount of time, any
// non-executable transactions queued up are dropped to prevent wasting resources
// on shuffling them around.
//
// This logic should not hold for local transactions, unless the local tracking
// mechanism is disabled.
func TestTransactionQueueTimeLimiting(t *testing.T)         { testTransactionQueueTimeLimiting(t, false) }
func TestTransactionQueueTimeLimitingNoLocals(t *testing.T) { testTransactionQueueTimeLimiting(t, true) }

func testTransactionQueueTimeLimiting(t *testing.T, nolocals bool) {
    // Reduce the eviction interval to a testable amount
    defer func(old time.Duration) { evictionInterval = old }(evictionInterval)
    evictionInterval = time.Second

    // Create the pool to test the non-expiration enforcement
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.Lifetime = time.Second
    config.NoLocals = nolocals

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create two test accounts to ensure remotes expire but locals do not
    local, _ := crypto.GenerateKey()
    remote, _ := crypto.GenerateKey()

    pool.currentState.AddBalance(crypto.PubkeyToAddress(local.PublicKey), big.NewInt(1000000000))
    pool.currentState.AddBalance(crypto.PubkeyToAddress(remote.PublicKey), big.NewInt(1000000000))

    // Add the two transactions and ensure they both are queued up
    if err := pool.AddLocal(pricedTransaction(1, 100000, big.NewInt(1), local)); err != nil {
        t.Fatalf("failed to add local transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(1, 100000, big.NewInt(1), remote)); err != nil {
        t.Fatalf("failed to add remote transaction: %v", err)
    }
    pending, queued := pool.Stats()
    if pending != 0 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 0)
    }
    if queued != 2 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 2)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Wait a bit for eviction to run and clean up any leftovers, and ensure only the local remains
    time.Sleep(2 * config.Lifetime)

    pending, queued = pool.Stats()
    if pending != 0 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 0)
    }
    if nolocals {
        if queued != 0 {
            t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
        }
    } else {
        if queued != 1 {
            t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 1)
        }
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that even if the transaction count belonging to a single account goes
// above some threshold, as long as the transactions are executable, they are
// accepted.
func TestTransactionPendingLimiting(t *testing.T) {
    t.Parallel()

    // Create a test account and fund it
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    // Keep track of transaction events to ensure all executables get announced
    events := make(chan TxPreEvent, testTxPoolConfig.AccountQueue+5)
    sub := pool.txFeed.Subscribe(events)
    defer sub.Unsubscribe()

    // Keep queuing up transactions and make sure all above a limit are dropped
    for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
        if err := pool.AddRemote(transaction(i, 100000, key)); err != nil {
            t.Fatalf("tx %d: failed to add transaction: %v", i, err)
        }
        if pool.pending[account].Len() != int(i)+1 {
            t.Errorf("tx %d: pending pool size mismatch: have %d, want %d", i, pool.pending[account].Len(), i+1)
        }
        if len(pool.queue) != 0 {
            t.Errorf("tx %d: queue size mismatch: have %d, want %d", i, pool.queue[account].Len(), 0)
        }
    }
    if len(pool.all) != int(testTxPoolConfig.AccountQueue+5) {
        t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), testTxPoolConfig.AccountQueue+5)
    }
    if err := validateEvents(events, int(testTxPoolConfig.AccountQueue+5)); err != nil {
        t.Fatalf("event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that the transaction limits are enforced the same way irrelevant whether
// the transactions are added one by one or in batches.
func TestTransactionQueueLimitingEquivalency(t *testing.T)   { testTransactionLimitingEquivalency(t, 1) }
func TestTransactionPendingLimitingEquivalency(t *testing.T) { testTransactionLimitingEquivalency(t, 0) }

func testTransactionLimitingEquivalency(t *testing.T, origin uint64) {
    t.Parallel()

    // Add a batch of transactions to a pool one by one
    pool1, key1 := setupTxPool()
    defer pool1.Stop()

    account1, _ := deriveSender(transaction(0, 0, key1))
    pool1.currentState.AddBalance(account1, big.NewInt(1000000))

    for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
        if err := pool1.AddRemote(transaction(origin+i, 100000, key1)); err != nil {
            t.Fatalf("tx %d: failed to add transaction: %v", i, err)
        }
    }
    // Add a batch of transactions to a pool in one big batch
    pool2, key2 := setupTxPool()
    defer pool2.Stop()

    account2, _ := deriveSender(transaction(0, 0, key2))
    pool2.currentState.AddBalance(account2, big.NewInt(1000000))

    txs := []*types.Transaction{}
    for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
        txs = append(txs, transaction(origin+i, 100000, key2))
    }
    pool2.AddRemotes(txs)

    // Ensure the batch optimization honors the same pool mechanics
    if len(pool1.pending) != len(pool2.pending) {
        t.Errorf("pending transaction count mismatch: one-by-one algo: %d, batch algo: %d", len(pool1.pending), len(pool2.pending))
    }
    if len(pool1.queue) != len(pool2.queue) {
        t.Errorf("queued transaction count mismatch: one-by-one algo: %d, batch algo: %d", len(pool1.queue), len(pool2.queue))
    }
    if len(pool1.all) != len(pool2.all) {
        t.Errorf("total transaction count mismatch: one-by-one algo %d, batch algo %d", len(pool1.all), len(pool2.all))
    }
    if err := validateTxPoolInternals(pool1); err != nil {
        t.Errorf("pool 1 internal state corrupted: %v", err)
    }
    if err := validateTxPoolInternals(pool2); err != nil {
        t.Errorf("pool 2 internal state corrupted: %v", err)
    }
}

// Tests that if the transaction count belonging to multiple accounts go above
// some hard threshold, the higher transactions are dropped to prevent DOS
// attacks.
func TestTransactionPendingGlobalLimiting(t *testing.T) {
    t.Parallel()

    // Create the pool to test the limit enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.GlobalSlots = config.AccountSlots * 10

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create a number of test accounts and fund them
    keys := make([]*ecdsa.PrivateKey, 5)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    // Generate and queue a batch of transactions
    nonces := make(map[common.Address]uint64)

    txs := types.Transactions{}
    for _, key := range keys {
        addr := crypto.PubkeyToAddress(key.PublicKey)
        for j := 0; j < int(config.GlobalSlots)/len(keys)*2; j++ {
            txs = append(txs, transaction(nonces[addr], 100000, key))
            nonces[addr]++
        }
    }
    // Import the batch and verify that limits have been enforced
    pool.AddRemotes(txs)

    pending := 0
    for _, list := range pool.pending {
        pending += list.Len()
    }
    if pending > int(config.GlobalSlots) {
        t.Fatalf("total pending transactions overflow allowance: %d > %d", pending, config.GlobalSlots)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that if transactions start being capped, transactions are also removed from 'all'
func TestTransactionCapClearsFromAll(t *testing.T) {
    t.Parallel()

    // Create the pool to test the limit enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.AccountSlots = 2
    config.AccountQueue = 2
    config.GlobalSlots = 8

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create a number of test accounts and fund them
    key, _ := crypto.GenerateKey()
    addr := crypto.PubkeyToAddress(key.PublicKey)
    pool.currentState.AddBalance(addr, big.NewInt(1000000))

    txs := types.Transactions{}
    for j := 0; j < int(config.GlobalSlots)*2; j++ {
        txs = append(txs, transaction(uint64(j), 100000, key))
    }
    // Import the batch and verify that limits have been enforced
    pool.AddRemotes(txs)
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that if the transaction count belonging to multiple accounts go above
// some hard threshold, if they are under the minimum guaranteed slot count then
// the transactions are still kept.
func TestTransactionPendingMinimumAllowance(t *testing.T) {
    t.Parallel()

    // Create the pool to test the limit enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.GlobalSlots = 0

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create a number of test accounts and fund them
    keys := make([]*ecdsa.PrivateKey, 5)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    // Generate and queue a batch of transactions
    nonces := make(map[common.Address]uint64)

    txs := types.Transactions{}
    for _, key := range keys {
        addr := crypto.PubkeyToAddress(key.PublicKey)
        for j := 0; j < int(config.AccountSlots)*2; j++ {
            txs = append(txs, transaction(nonces[addr], 100000, key))
            nonces[addr]++
        }
    }
    // Import the batch and verify that limits have been enforced
    pool.AddRemotes(txs)

    for addr, list := range pool.pending {
        if list.Len() != int(config.AccountSlots) {
            t.Errorf("addr %x: total pending transactions mismatch: have %d, want %d", addr, list.Len(), config.AccountSlots)
        }
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that setting the transaction pool gas price to a higher value correctly
// discards everything cheaper than that and moves any gapped transactions back
// from the pending pool to the queue.
//
// Note, local transactions are never allowed to be dropped.
func TestTransactionPoolRepricing(t *testing.T) {
    t.Parallel()

    // Create the pool to test the pricing enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Keep track of transaction events to ensure all executables get announced
    events := make(chan TxPreEvent, 32)
    sub := pool.txFeed.Subscribe(events)
    defer sub.Unsubscribe()

    // Create a number of test accounts and fund them
    keys := make([]*ecdsa.PrivateKey, 4)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    // Generate and queue a batch of transactions, both pending and queued
    txs := types.Transactions{}

    txs = append(txs, pricedTransaction(0, 100000, big.NewInt(2), keys[0]))
    txs = append(txs, pricedTransaction(1, 100000, big.NewInt(1), keys[0]))
    txs = append(txs, pricedTransaction(2, 100000, big.NewInt(2), keys[0]))

    txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[1]))
    txs = append(txs, pricedTransaction(1, 100000, big.NewInt(2), keys[1]))
    txs = append(txs, pricedTransaction(2, 100000, big.NewInt(2), keys[1]))

    txs = append(txs, pricedTransaction(1, 100000, big.NewInt(2), keys[2]))
    txs = append(txs, pricedTransaction(2, 100000, big.NewInt(1), keys[2]))
    txs = append(txs, pricedTransaction(3, 100000, big.NewInt(2), keys[2]))

    ltx := pricedTransaction(0, 100000, big.NewInt(1), keys[3])

    // Import the batch and that both pending and queued transactions match up
    pool.AddRemotes(txs)
    pool.AddLocal(ltx)

    pending, queued := pool.Stats()
    if pending != 7 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 7)
    }
    if queued != 3 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 3)
    }
    if err := validateEvents(events, 7); err != nil {
        t.Fatalf("original event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Reprice the pool and check that underpriced transactions get dropped
    pool.SetGasPrice(big.NewInt(2))

    pending, queued = pool.Stats()
    if pending != 2 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 2)
    }
    if queued != 5 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 5)
    }
    if err := validateEvents(events, 0); err != nil {
        t.Fatalf("reprice event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Check that we can't add the old transactions back
    if err := pool.AddRemote(pricedTransaction(1, 100000, big.NewInt(1), keys[0])); err != ErrUnderpriced {
        t.Fatalf("adding underpriced pending transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), keys[1])); err != ErrUnderpriced {
        t.Fatalf("adding underpriced pending transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(1), keys[2])); err != ErrUnderpriced {
        t.Fatalf("adding underpriced queued transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
    }
    if err := validateEvents(events, 0); err != nil {
        t.Fatalf("post-reprice event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // However we can add local underpriced transactions
    tx := pricedTransaction(1, 100000, big.NewInt(1), keys[3])
    if err := pool.AddLocal(tx); err != nil {
        t.Fatalf("failed to add underpriced local transaction: %v", err)
    }
    if pending, _ = pool.Stats(); pending != 3 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 3)
    }
    if err := validateEvents(events, 1); err != nil {
        t.Fatalf("post-reprice local event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // And we can fill gaps with properly priced transactions
    if err := pool.AddRemote(pricedTransaction(1, 100000, big.NewInt(2), keys[0])); err != nil {
        t.Fatalf("failed to add pending transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(2), keys[1])); err != nil {
        t.Fatalf("failed to add pending transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(2), keys[2])); err != nil {
        t.Fatalf("failed to add queued transaction: %v", err)
    }
    if err := validateEvents(events, 5); err != nil {
        t.Fatalf("post-reprice event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that setting the transaction pool gas price to a higher value does not
// remove local transactions.
func TestTransactionPoolRepricingKeepsLocals(t *testing.T) {
    t.Parallel()

    // Create the pool to test the pricing enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create a number of test accounts and fund them
    keys := make([]*ecdsa.PrivateKey, 3)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000*1000000))
    }
    // Create transaction (both pending and queued) with a linearly growing gasprice
    for i := uint64(0); i < 500; i++ {
        // Add pending
        p_tx := pricedTransaction(i, 100000, big.NewInt(int64(i)), keys[2])
        if err := pool.AddLocal(p_tx); err != nil {
            t.Fatal(err)
        }
        // Add queued
        q_tx := pricedTransaction(i+501, 100000, big.NewInt(int64(i)), keys[2])
        if err := pool.AddLocal(q_tx); err != nil {
            t.Fatal(err)
        }
    }
    pending, queued := pool.Stats()
    expPending, expQueued := 500, 500
    validate := func() {
        pending, queued = pool.Stats()
        if pending != expPending {
            t.Fatalf("pending transactions mismatched: have %d, want %d", pending, expPending)
        }
        if queued != expQueued {
            t.Fatalf("queued transactions mismatched: have %d, want %d", queued, expQueued)
        }

        if err := validateTxPoolInternals(pool); err != nil {
            t.Fatalf("pool internal state corrupted: %v", err)
        }
    }
    validate()

    // Reprice the pool and check that nothing is dropped
    pool.SetGasPrice(big.NewInt(2))
    validate()

    pool.SetGasPrice(big.NewInt(2))
    pool.SetGasPrice(big.NewInt(4))
    pool.SetGasPrice(big.NewInt(8))
    pool.SetGasPrice(big.NewInt(100))
    validate()
}

// Tests that when the pool reaches its global transaction limit, underpriced
// transactions are gradually shifted out for more expensive ones and any gapped
// pending transactions are moved into the queue.
//
// Note, local transactions are never allowed to be dropped.
func TestTransactionPoolUnderpricing(t *testing.T) {
    t.Parallel()

    // Create the pool to test the pricing enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.GlobalSlots = 2
    config.GlobalQueue = 2

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Keep track of transaction events to ensure all executables get announced
    events := make(chan TxPreEvent, 32)
    sub := pool.txFeed.Subscribe(events)
    defer sub.Unsubscribe()

    // Create a number of test accounts and fund them
    keys := make([]*ecdsa.PrivateKey, 3)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    // Generate and queue a batch of transactions, both pending and queued
    txs := types.Transactions{}

    txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[0]))
    txs = append(txs, pricedTransaction(1, 100000, big.NewInt(2), keys[0]))

    txs = append(txs, pricedTransaction(1, 100000, big.NewInt(1), keys[1]))

    ltx := pricedTransaction(0, 100000, big.NewInt(1), keys[2])

    // Import the batch and that both pending and queued transactions match up
    pool.AddRemotes(txs)
    pool.AddLocal(ltx)

    pending, queued := pool.Stats()
    if pending != 3 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 3)
    }
    if queued != 1 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 1)
    }
    if err := validateEvents(events, 3); err != nil {
        t.Fatalf("original event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Ensure that adding an underpriced transaction on block limit fails
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), keys[1])); err != ErrUnderpriced {
        t.Fatalf("adding underpriced pending transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
    }
    // Ensure that adding high priced transactions drops cheap ones, but not own
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(3), keys[1])); err != nil { // +K1:0 => -K1:1 => Pend K0:0, K0:1, K1:0, K2:0; Que -
        t.Fatalf("failed to add well priced transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(4), keys[1])); err != nil { // +K1:2 => -K0:0 => Pend K1:0, K2:0; Que K0:1 K1:2
        t.Fatalf("failed to add well priced transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(3, 100000, big.NewInt(5), keys[1])); err != nil { // +K1:3 => -K0:1 => Pend K1:0, K2:0; Que K1:2 K1:3
        t.Fatalf("failed to add well priced transaction: %v", err)
    }
    pending, queued = pool.Stats()
    if pending != 2 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 2)
    }
    if queued != 2 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 2)
    }
    if err := validateEvents(events, 1); err != nil {
        t.Fatalf("additional event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Ensure that adding local transactions can push out even higher priced ones
    tx := pricedTransaction(1, 100000, big.NewInt(0), keys[2])
    if err := pool.AddLocal(tx); err != nil {
        t.Fatalf("failed to add underpriced local transaction: %v", err)
    }
    pending, queued = pool.Stats()
    if pending != 2 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 2)
    }
    if queued != 2 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 2)
    }
    if err := validateEvents(events, 1); err != nil {
        t.Fatalf("local event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that more expensive transactions push out cheap ones from the pool, but
// without producing instability by creating gaps that start jumping transactions
// back and forth between queued/pending.
func TestTransactionPoolStableUnderpricing(t *testing.T) {
    t.Parallel()

    // Create the pool to test the pricing enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.GlobalSlots = 128
    config.GlobalQueue = 0

    pool := NewTxPool(config, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Keep track of transaction events to ensure all executables get announced
    events := make(chan TxPreEvent, 32)
    sub := pool.txFeed.Subscribe(events)
    defer sub.Unsubscribe()

    // Create a number of test accounts and fund them
    keys := make([]*ecdsa.PrivateKey, 2)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    // Fill up the entire queue with the same transaction price points
    txs := types.Transactions{}
    for i := uint64(0); i < config.GlobalSlots; i++ {
        txs = append(txs, pricedTransaction(i, 100000, big.NewInt(1), keys[0]))
    }
    pool.AddRemotes(txs)

    pending, queued := pool.Stats()
    if pending != int(config.GlobalSlots) {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, config.GlobalSlots)
    }
    if queued != 0 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
    }
    if err := validateEvents(events, int(config.GlobalSlots)); err != nil {
        t.Fatalf("original event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Ensure that adding high priced transactions drops a cheap, but doesn't produce a gap
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(3), keys[1])); err != nil {
        t.Fatalf("failed to add well priced transaction: %v", err)
    }
    pending, queued = pool.Stats()
    if pending != int(config.GlobalSlots) {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, config.GlobalSlots)
    }
    if queued != 0 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
    }
    if err := validateEvents(events, 1); err != nil {
        t.Fatalf("additional event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that the pool rejects replacement transactions that don't meet the minimum
// price bump required.
func TestTransactionReplacement(t *testing.T) {
    t.Parallel()

    // Create the pool to test the pricing enforcement with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Keep track of transaction events to ensure all executables get announced
    events := make(chan TxPreEvent, 32)
    sub := pool.txFeed.Subscribe(events)
    defer sub.Unsubscribe()

    // Create a test account to add transactions with
    key, _ := crypto.GenerateKey()
    pool.currentState.AddBalance(crypto.PubkeyToAddress(key.PublicKey), big.NewInt(1000000000))

    // Add pending transactions, ensuring the minimum price bump is enforced for replacement (for ultra low prices too)
    price := int64(100)
    threshold := (price * (100 + int64(testTxPoolConfig.PriceBump))) / 100

    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), key)); err != nil {
        t.Fatalf("failed to add original cheap pending transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100001, big.NewInt(1), key)); err != ErrReplaceUnderpriced {
        t.Fatalf("original cheap pending transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(2), key)); err != nil {
        t.Fatalf("failed to replace original cheap pending transaction: %v", err)
    }
    if err := validateEvents(events, 2); err != nil {
        t.Fatalf("cheap replacement event firing failed: %v", err)
    }

    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(price), key)); err != nil {
        t.Fatalf("failed to add original proper pending transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100001, big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
        t.Fatalf("original proper pending transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(threshold), key)); err != nil {
        t.Fatalf("failed to replace original proper pending transaction: %v", err)
    }
    if err := validateEvents(events, 2); err != nil {
        t.Fatalf("proper replacement event firing failed: %v", err)
    }
    // Add queued transactions, ensuring the minimum price bump is enforced for replacement (for ultra low prices too)
    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(1), key)); err != nil {
        t.Fatalf("failed to add original cheap queued transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100001, big.NewInt(1), key)); err != ErrReplaceUnderpriced {
        t.Fatalf("original cheap queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(2), key)); err != nil {
        t.Fatalf("failed to replace original cheap queued transaction: %v", err)
    }

    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(price), key)); err != nil {
        t.Fatalf("failed to add original proper queued transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100001, big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
        t.Fatalf("original proper queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
    }
    if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(threshold), key)); err != nil {
        t.Fatalf("failed to replace original proper queued transaction: %v", err)
    }

    if err := validateEvents(events, 0); err != nil {
        t.Fatalf("queued replacement event firing failed: %v", err)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
}

// Tests that local transactions are journaled to disk, but remote transactions
// get discarded between restarts.
func TestTransactionJournaling(t *testing.T)         { testTransactionJournaling(t, false) }
func TestTransactionJournalingNoLocals(t *testing.T) { testTransactionJournaling(t, true) }

func testTransactionJournaling(t *testing.T, nolocals bool) {
    t.Parallel()

    // Create a temporary file for the journal
    file, err := ioutil.TempFile("", "")
    if err != nil {
        t.Fatalf("failed to create temporary journal: %v", err)
    }
    journal := file.Name()
    defer os.Remove(journal)

    // Clean up the temporary file, we only need the path for now
    file.Close()
    os.Remove(journal)

    // Create the original pool to inject transaction into the journal
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    config := testTxPoolConfig
    config.NoLocals = nolocals
    config.Journal = journal
    config.Rejournal = time.Second

    pool := NewTxPool(config, params.TestChainConfig, blockchain)

    // Create two test accounts to ensure remotes expire but locals do not
    local, _ := crypto.GenerateKey()
    remote, _ := crypto.GenerateKey()

    pool.currentState.AddBalance(crypto.PubkeyToAddress(local.PublicKey), big.NewInt(1000000000))
    pool.currentState.AddBalance(crypto.PubkeyToAddress(remote.PublicKey), big.NewInt(1000000000))

    // Add three local and a remote transactions and ensure they are queued up
    if err := pool.AddLocal(pricedTransaction(0, 100000, big.NewInt(1), local)); err != nil {
        t.Fatalf("failed to add local transaction: %v", err)
    }
    if err := pool.AddLocal(pricedTransaction(1, 100000, big.NewInt(1), local)); err != nil {
        t.Fatalf("failed to add local transaction: %v", err)
    }
    if err := pool.AddLocal(pricedTransaction(2, 100000, big.NewInt(1), local)); err != nil {
        t.Fatalf("failed to add local transaction: %v", err)
    }
    if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), remote)); err != nil {
        t.Fatalf("failed to add remote transaction: %v", err)
    }
    pending, queued := pool.Stats()
    if pending != 4 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 4)
    }
    if queued != 0 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Terminate the old pool, bump the local nonce, create a new pool and ensure relevant transaction survive
    pool.Stop()
    statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 1)
    blockchain = &testBlockChain{statedb, 1000000, new(event.Feed)}

    pool = NewTxPool(config, params.TestChainConfig, blockchain)

    pending, queued = pool.Stats()
    if queued != 0 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
    }
    if nolocals {
        if pending != 0 {
            t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 0)
        }
    } else {
        if pending != 2 {
            t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 2)
        }
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Bump the nonce temporarily and ensure the newly invalidated transaction is removed
    statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 2)
    pool.lockedReset(nil, nil)
    time.Sleep(2 * config.Rejournal)
    pool.Stop()

    statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 1)
    blockchain = &testBlockChain{statedb, 1000000, new(event.Feed)}
    pool = NewTxPool(config, params.TestChainConfig, blockchain)

    pending, queued = pool.Stats()
    if pending != 0 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 0)
    }
    if nolocals {
        if queued != 0 {
            t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
        }
    } else {
        if queued != 1 {
            t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 1)
        }
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    pool.Stop()
}

// TestTransactionStatusCheck tests that the pool can correctly retrieve the
// pending status of individual transactions.
func TestTransactionStatusCheck(t *testing.T) {
    t.Parallel()

    // Create the pool to test the status retrievals with
    db, _ := ethdb.NewMemDatabase()
    statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
    blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}

    pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
    defer pool.Stop()

    // Create the test accounts to check various transaction statuses with
    keys := make([]*ecdsa.PrivateKey, 3)
    for i := 0; i < len(keys); i++ {
        keys[i], _ = crypto.GenerateKey()
        pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
    }
    // Generate and queue a batch of transactions, both pending and queued
    txs := types.Transactions{}

    txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[0])) // Pending only
    txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[1])) // Pending and queued
    txs = append(txs, pricedTransaction(2, 100000, big.NewInt(1), keys[1]))
    txs = append(txs, pricedTransaction(2, 100000, big.NewInt(1), keys[2])) // Queued only

    // Import the transaction and ensure they are correctly added
    pool.AddRemotes(txs)

    pending, queued := pool.Stats()
    if pending != 2 {
        t.Fatalf("pending transactions mismatched: have %d, want %d", pending, 2)
    }
    if queued != 2 {
        t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 2)
    }
    if err := validateTxPoolInternals(pool); err != nil {
        t.Fatalf("pool internal state corrupted: %v", err)
    }
    // Retrieve the status of each transaction and validate them
    hashes := make([]common.Hash, len(txs))
    for i, tx := range txs {
        hashes[i] = tx.Hash()
    }
    hashes = append(hashes, common.Hash{})

    statuses := pool.Status(hashes)
    expect := []TxStatus{TxStatusPending, TxStatusPending, TxStatusQueued, TxStatusQueued, TxStatusUnknown}

    for i := 0; i < len(statuses); i++ {
        if statuses[i] != expect[i] {
            t.Errorf("transaction %d: status mismatch: have %v, want %v", i, statuses[i], expect[i])
        }
    }
}

// Benchmarks the speed of validating the contents of the pending queue of the
// transaction pool.
func BenchmarkPendingDemotion100(b *testing.B)   { benchmarkPendingDemotion(b, 100) }
func BenchmarkPendingDemotion1000(b *testing.B)  { benchmarkPendingDemotion(b, 1000) }
func BenchmarkPendingDemotion10000(b *testing.B) { benchmarkPendingDemotion(b, 10000) }

func benchmarkPendingDemotion(b *testing.B, size int) {
    // Add a batch of transactions to a pool one by one
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    for i := 0; i < size; i++ {
        tx := transaction(uint64(i), 100000, key)
        pool.promoteTx(account, tx.Hash(), tx)
    }
    // Benchmark the speed of pool validation
    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        pool.demoteUnexecutables()
    }
}

// Benchmarks the speed of scheduling the contents of the future queue of the
// transaction pool.
func BenchmarkFuturePromotion100(b *testing.B)   { benchmarkFuturePromotion(b, 100) }
func BenchmarkFuturePromotion1000(b *testing.B)  { benchmarkFuturePromotion(b, 1000) }
func BenchmarkFuturePromotion10000(b *testing.B) { benchmarkFuturePromotion(b, 10000) }

func benchmarkFuturePromotion(b *testing.B, size int) {
    // Add a batch of transactions to a pool one by one
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    for i := 0; i < size; i++ {
        tx := transaction(uint64(1+i), 100000, key)
        pool.enqueueTx(tx.Hash(), tx)
    }
    // Benchmark the speed of pool validation
    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        pool.promoteExecutables(nil)
    }
}

// Benchmarks the speed of iterative transaction insertion.
func BenchmarkPoolInsert(b *testing.B) {
    // Generate a batch of transactions to enqueue into the pool
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    txs := make(types.Transactions, b.N)
    for i := 0; i < b.N; i++ {
        txs[i] = transaction(uint64(i), 100000, key)
    }
    // Benchmark importing the transactions into the queue
    b.ResetTimer()
    for _, tx := range txs {
        pool.AddRemote(tx)
    }
}

// Benchmarks the speed of batched transaction insertion.
func BenchmarkPoolBatchInsert100(b *testing.B)   { benchmarkPoolBatchInsert(b, 100) }
func BenchmarkPoolBatchInsert1000(b *testing.B)  { benchmarkPoolBatchInsert(b, 1000) }
func BenchmarkPoolBatchInsert10000(b *testing.B) { benchmarkPoolBatchInsert(b, 10000) }

func benchmarkPoolBatchInsert(b *testing.B, size int) {
    // Generate a batch of transactions to enqueue into the pool
    pool, key := setupTxPool()
    defer pool.Stop()

    account, _ := deriveSender(transaction(0, 0, key))
    pool.currentState.AddBalance(account, big.NewInt(1000000))

    batches := make([]types.Transactions, b.N)
    for i := 0; i < b.N; i++ {
        batches[i] = make(types.Transactions, size)
        for j := 0; j < size; j++ {
            batches[i][j] = transaction(uint64(size*i+j), 100000, key)
        }
    }
    // Benchmark importing the transactions into the queue
    b.ResetTimer()
    for _, batch := range batches {
        pool.AddRemotes(batch)
    }
}