// Copyright (c) 2011-present The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <test/util/setup_common.h>

#include <addrman.h>

#include <banman.h>

#include <chainparams.h>

#include <common/system.h>

#include <consensus/consensus.h>

#include <consensus/params.h>

#include <consensus/validation.h>

#include <crypto/sha256.h>

#include <init.h>

#include <init/common.h>

#include <interfaces/chain.h>

#include <kernel/mempool_entry.h>

#include <logging.h>

#include <net.h>

#include <net_processing.h>

#include <node/blockstorage.h>

#include <node/chainstate.h>

#include <node/context.h>

#include <node/kernel_notifications.h>

#include <node/mempool_args.h>

#include <node/miner.h>

#include <node/peerman_args.h>

#include <node/warnings.h>

#include <noui.h>

#include <policy/fees.h>

#include <pow.h>

#include <random.h>

#include <rpc/blockchain.h>

#include <rpc/register.h>

#include <rpc/server.h>

#include <scheduler.h>

#include <script/sigcache.h>

#include <streams.h>

#include <test/util/coverage.h>

#include <test/util/net.h>

#include <test/util/random.h>

#include <test/util/transaction_utils.h>

#include <test/util/txmempool.h>

#include <txdb.h>

#include <txmempool.h>

#include <util/chaintype.h>

#include <util/check.h>

#include <util/fs_helpers.h>

#include <util/rbf.h>

#include <util/strencodings.h>

#include <util/string.h>

#include <util/task_runner.h>

#include <util/thread.h>

#include <util/threadnames.h>

#include <util/time.h>

#include <util/translation.h>

#include <util/vector.h>

#include <validation.h>

#include <validationinterface.h>

#include <walletinitinterface.h>

#include <algorithm>

#include <future>

#include <functional>

#include <stdexcept>

using namespace util::hex_literals;

using node::ApplyArgsManOptions;

using node::BlockAssembler;

using node::BlockManager;

using node::KernelNotifications;

using node::LoadChainstate;

using node::RegenerateCommitments;

using node::VerifyLoadedChainstate;

const TranslateFn G_TRANSLATION_FUN{nullptr};

constexpr inline auto TEST_DIR_PATH_ELEMENT{"test_common bitcoin"}; // Includes a space to catch possible path escape issues.

/** Random context to get unique temp data dirs. Separate from m_rng, which can be seeded from a const env var */

static FastRandomContext g_rng_temp_path;

static const bool g_rng_temp_path_init{[] {

    // Must be initialized before any SeedRandomForTest

    Assert(!g_used_g_prng);

    (void)g_rng_temp_path.rand64();

    g_used_g_prng = false;

    ResetCoverageCounters(); // The seed strengthen in SeedStartup is not deterministic, so exclude it from coverage counts

    return true;

}()};

struct NetworkSetup

{

    NetworkSetup()

    {

        Assert(SetupNetworking());

    }

};

static NetworkSetup g_networksetup_instance;

void SetupCommonTestArgs(ArgsManager& argsman)

{

    argsman.AddArg("-testdatadir", strprintf("Custom data directory (default: %s<random_string>)", fs::PathToString(fs::temp_directory_path() / TEST_DIR_PATH_ELEMENT / "")),

                   ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);

}

/** Test setup failure */

static void ExitFailure(std::string_view str_err)

{

    std::cerr << str_err << std::endl;

    exit(EXIT_FAILURE);

}

BasicTestingSetup::BasicTestingSetup(const ChainType chainType, TestOpts opts)

    : m_args{}

{

    if (!EnableFuzzDeterminism()) {

        SeedRandomForTest(SeedRand::FIXED_SEED);

    }

    // Reset globals

    fDiscover = true;

    fListen = true;

    SetRPCWarmupStarting();

    g_reachable_nets.Reset();

    ClearLocal();

    m_node.shutdown_signal = &m_interrupt;

    m_node.shutdown_request = [this]{ return m_interrupt(); };

    m_node.args = &gArgs;

    std::vector<const char*> arguments = Cat(

        {

            "dummy",

            "-printtoconsole=0",

            "-logsourcelocations",

            "-logtimemicros",

            "-logthreadnames",

            "-loglevel=trace",

            "-debug",

            "-debugexclude=libevent",

            "-debugexclude=leveldb",

        },

        opts.extra_args);

    if (G_TEST_COMMAND_LINE_ARGUMENTS) {

        arguments = Cat(arguments, G_TEST_COMMAND_LINE_ARGUMENTS());

    }

    util::ThreadRename("test");

    gArgs.ClearPathCache();

    {

        SetupServerArgs(*m_node.args);

        SetupCommonTestArgs(*m_node.args);

        std::string error;

        if (!m_node.args->ParseParameters(arguments.size(), arguments.data(), error)) {

            m_node.args->ClearArgs();

            throw std::runtime_error{error};

        }

    }

    const std::string test_name{G_TEST_GET_FULL_NAME ? G_TEST_GET_FULL_NAME() : ""};

    if (!m_node.args->IsArgSet("-testdatadir")) {

        // To avoid colliding with a leftover prior datadir, and to allow

        // tests, such as the fuzz tests to run in several processes at the

        // same time, add a random element to the path. Keep it small enough to

        // avoid a MAX_PATH violation on Windows.

        const auto rand{HexStr(g_rng_temp_path.randbytes(10))};

        m_path_root = fs::temp_directory_path() / TEST_DIR_PATH_ELEMENT / test_name / rand;

        TryCreateDirectories(m_path_root);

    } else {

        // Custom data directory

        m_has_custom_datadir = true;

        fs::path root_dir{m_node.args->GetPathArg("-testdatadir")};

        if (root_dir.empty()) ExitFailure("-testdatadir argument is empty, please specify a path");

        root_dir = fs::absolute(root_dir);

        m_path_lock = root_dir / TEST_DIR_PATH_ELEMENT / fs::PathFromString(test_name);

        m_path_root = m_path_lock / "datadir";

        // Try to obtain the lock; if unsuccessful don't disturb the existing test.

        TryCreateDirectories(m_path_lock);

        if (util::LockDirectory(m_path_lock, ".lock", /*probe_only=*/false) != util::LockResult::Success) {

            ExitFailure("Cannot obtain a lock on test data lock directory " + fs::PathToString(m_path_lock) + '\n' + "The test executable is probably already running.");

        }

        // Always start with a fresh data directory; this doesn't delete the .lock file located one level above.

        fs::remove_all(m_path_root);

        if (!TryCreateDirectories(m_path_root)) ExitFailure("Cannot create test data directory");

        // Print the test directory name if custom.

        std::cout << "Test directory (will not be deleted): " << m_path_root << std::endl;

    }

    m_args.ForceSetArg("-datadir", fs::PathToString(m_path_root));

    gArgs.ForceSetArg("-datadir", fs::PathToString(m_path_root));

    SelectParams(chainType);

    if (G_TEST_LOG_FUN) LogInstance().PushBackCallback(G_TEST_LOG_FUN);

    InitLogging(*m_node.args);

    AppInitParameterInteraction(*m_node.args);

    LogInstance().StartLogging();

    m_node.warnings = std::make_unique<node::Warnings>();

    m_node.kernel = std::make_unique<kernel::Context>();

    m_node.ecc_context = std::make_unique<ECC_Context>();

    SetupEnvironment();

    m_node.chain = interfaces::MakeChain(m_node);

    static bool noui_connected = false;

    if (!noui_connected) {

        noui_connect();

        noui_connected = true;

    }

}

BasicTestingSetup::~BasicTestingSetup()

{

    m_node.ecc_context.reset();

    m_node.kernel.reset();

    if (!EnableFuzzDeterminism()) {

        SetMockTime(0s); // Reset mocktime for following tests

    }

    LogInstance().DisconnectTestLogger();

    if (m_has_custom_datadir) {

        // Only remove the lock file, preserve the data directory.

        UnlockDirectory(m_path_lock, ".lock");

        fs::remove(m_path_lock / ".lock");

    } else {

        fs::remove_all(m_path_root);

    }

    // Clear all arguments except for -datadir, which GUI tests currently rely

    // on to be set even after the testing setup is destroyed.

    gArgs.ClearArgs();

    gArgs.ForceSetArg("-datadir", fs::PathToString(m_path_root));

}

ChainTestingSetup::ChainTestingSetup(const ChainType chainType, TestOpts opts)

    : BasicTestingSetup(chainType, opts)

{

    const CChainParams& chainparams = Params();

    // A task runner is required to prevent ActivateBestChain

    // from blocking due to queue overrun.

    if (opts.setup_validation_interface) {

        m_node.scheduler = std::make_unique<CScheduler>();

        m_node.scheduler->m_service_thread = std::thread(util::TraceThread, "scheduler", [&] { m_node.scheduler->serviceQueue(); });

        m_node.validation_signals =

            // Use synchronous task runner while fuzzing to avoid non-determinism

            EnableFuzzDeterminism() ?

                std::make_unique<ValidationSignals>(std::make_unique<util::ImmediateTaskRunner>()) :

                std::make_unique<ValidationSignals>(std::make_unique<SerialTaskRunner>(*m_node.scheduler));

        {

            // Ensure deterministic coverage by waiting for m_service_thread to be running

            std::promise<void> promise;

            m_node.scheduler->scheduleFromNow([&promise] { promise.set_value(); }, 0ms);

            promise.get_future().wait();

        }

    }

    bilingual_str error{};

    m_node.mempool = std::make_unique<CTxMemPool>(MemPoolOptionsForTest(m_node), error);

    Assert(error.empty());

    m_node.warnings = std::make_unique<node::Warnings>();

    m_node.notifications = std::make_unique<KernelNotifications>(Assert(m_node.shutdown_request), m_node.exit_status, *Assert(m_node.warnings));

    m_make_chainman = [this, &chainparams, opts] {

        Assert(!m_node.chainman);

        ChainstateManager::Options chainman_opts{

            .chainparams = chainparams,

            .datadir = m_args.GetDataDirNet(),

            .check_block_index = 1,

            .notifications = *m_node.notifications,

            .signals = m_node.validation_signals.get(),

            // Use no worker threads while fuzzing to avoid non-determinism

            .worker_threads_num = EnableFuzzDeterminism() ? 0 : 2,

        };

        if (opts.min_validation_cache) {

            chainman_opts.script_execution_cache_bytes = 0;

            chainman_opts.signature_cache_bytes = 0;

        }

        const BlockManager::Options blockman_opts{

            .chainparams = chainman_opts.chainparams,

            .blocks_dir = m_args.GetBlocksDirPath(),

            .notifications = chainman_opts.notifications,

            .block_tree_db_params = DBParams{

                .path = m_args.GetDataDirNet() / "blocks" / "index",

                .cache_bytes = m_kernel_cache_sizes.block_tree_db,

                .memory_only = opts.block_tree_db_in_memory,

                .wipe_data = m_args.GetBoolArg("-reindex", false),

            },

        };

        m_node.chainman = std::make_unique<ChainstateManager>(*Assert(m_node.shutdown_signal), chainman_opts, blockman_opts);

    };

    m_make_chainman();

}

ChainTestingSetup::~ChainTestingSetup()

{

    if (m_node.scheduler) m_node.scheduler->stop();

    if (m_node.validation_signals) m_node.validation_signals->FlushBackgroundCallbacks();

    m_node.connman.reset();

    m_node.banman.reset();

    m_node.addrman.reset();

    m_node.netgroupman.reset();

    m_node.args = nullptr;

    m_node.mempool.reset();

    Assert(!m_node.fee_estimator); // Each test must create a local object, if they wish to use the fee_estimator

    m_node.chainman.reset();

    m_node.validation_signals.reset();

    m_node.scheduler.reset();

}

void ChainTestingSetup::LoadVerifyActivateChainstate()

{

    auto& chainman{*Assert(m_node.chainman)};

    node::ChainstateLoadOptions options;

    options.mempool = Assert(m_node.mempool.get());

    options.coins_db_in_memory = m_coins_db_in_memory;

    options.wipe_chainstate_db = m_args.GetBoolArg("-reindex", false) || m_args.GetBoolArg("-reindex-chainstate", false);

    options.prune = chainman.m_blockman.IsPruneMode();

    options.check_blocks = m_args.GetIntArg("-checkblocks", DEFAULT_CHECKBLOCKS);

    options.check_level = m_args.GetIntArg("-checklevel", DEFAULT_CHECKLEVEL);

    options.require_full_verification = m_args.IsArgSet("-checkblocks") || m_args.IsArgSet("-checklevel");

    auto [status, error] = LoadChainstate(chainman, m_kernel_cache_sizes, options);

    assert(status == node::ChainstateLoadStatus::SUCCESS);

    std::tie(status, error) = VerifyLoadedChainstate(chainman, options);

    assert(status == node::ChainstateLoadStatus::SUCCESS);

    BlockValidationState state;

    if (!chainman.ActiveChainstate().ActivateBestChain(state)) {

        throw std::runtime_error(strprintf("ActivateBestChain failed. (%s)", state.ToString()));

    }

}

TestingSetup::TestingSetup(

    const ChainType chainType,

    TestOpts opts)

    : ChainTestingSetup(chainType, opts)

{

    m_coins_db_in_memory = opts.coins_db_in_memory;

    m_block_tree_db_in_memory = opts.block_tree_db_in_memory;

    // Ideally we'd move all the RPC tests to the functional testing framework

    // instead of unit tests, but for now we need these here.

    RegisterAllCoreRPCCommands(tableRPC);

    LoadVerifyActivateChainstate();

    if (!opts.setup_net) return;

    m_node.netgroupman = std::make_unique<NetGroupManager>(/*asmap=*/std::vector<bool>());

    m_node.addrman = std::make_unique<AddrMan>(*m_node.netgroupman,

                                               /*deterministic=*/false,

                                               m_node.args->GetIntArg("-checkaddrman", 0));

    m_node.banman = std::make_unique<BanMan>(m_args.GetDataDirBase() / "banlist", nullptr, DEFAULT_MISBEHAVING_BANTIME);

    m_node.connman = std::make_unique<ConnmanTestMsg>(0x1337, 0x1337, *m_node.addrman, *m_node.netgroupman, Params()); // Deterministic randomness for tests.

    PeerManager::Options peerman_opts;

    ApplyArgsManOptions(*m_node.args, peerman_opts);

    peerman_opts.deterministic_rng = true;

    m_node.peerman = PeerManager::make(*m_node.connman, *m_node.addrman,

                                       m_node.banman.get(), *m_node.chainman,

                                       *m_node.mempool, *m_node.warnings,

                                       peerman_opts);

    {

        CConnman::Options options;

        options.m_msgproc = m_node.peerman.get();

        m_node.connman->Init(options);

    }

}

TestChain100Setup::TestChain100Setup(

    const ChainType chain_type,

    TestOpts opts)

    : TestingSetup{ChainType::REGTEST, opts}

{

    SetMockTime(1598887952);

    constexpr std::array<unsigned char, 32> vchKey = {

        {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}};

    coinbaseKey.Set(vchKey.begin(), vchKey.end(), true);

    // Generate a 100-block chain:

    this->mineBlocks(COINBASE_MATURITY);

    {

        LOCK(::cs_main);

        assert(

            m_node.chainman->ActiveChain().Tip()->GetBlockHash().ToString() ==

            "0c8c5f79505775a0f6aed6aca2350718ceb9c6f2c878667864d5c7a6d8ffa2a6");

    }

}

void TestChain100Setup::mineBlocks(int num_blocks)

{

    CScript scriptPubKey = CScript() << ToByteVector(coinbaseKey.GetPubKey()) << OP_CHECKSIG;

    for (int i = 0; i < num_blocks; i++) {

        std::vector<CMutableTransaction> noTxns;

        CBlock b = CreateAndProcessBlock(noTxns, scriptPubKey);

        SetMockTime(GetTime() + 1);

        m_coinbase_txns.push_back(b.vtx[0]);

    }

}

CBlock TestChain100Setup::CreateBlock(

    const std::vector<CMutableTransaction>& txns,

    const CScript& scriptPubKey,

    Chainstate& chainstate)

{

    BlockAssembler::Options options;

    options.coinbase_output_script = scriptPubKey;

    CBlock block = BlockAssembler{chainstate, nullptr, options}.CreateNewBlock()->block;

    Assert(block.vtx.size() == 1);

    for (const CMutableTransaction& tx : txns) {

        block.vtx.push_back(MakeTransactionRef(tx));

    }

    RegenerateCommitments(block, *Assert(m_node.chainman));

    while (!CheckProofOfWork(block.GetHash(), block.nBits, m_node.chainman->GetConsensus())) ++block.nNonce;

    return block;

}

CBlock TestChain100Setup::CreateAndProcessBlock(

    const std::vector<CMutableTransaction>& txns,

    const CScript& scriptPubKey,

    Chainstate* chainstate)

{

    if (!chainstate) {

        chainstate = &Assert(m_node.chainman)->ActiveChainstate();

    }

    CBlock block = this->CreateBlock(txns, scriptPubKey, *chainstate);

    std::shared_ptr<const CBlock> shared_pblock = std::make_shared<const CBlock>(block);

    Assert(m_node.chainman)->ProcessNewBlock(shared_pblock, true, true, nullptr);

    return block;

}

std::pair<CMutableTransaction, CAmount> TestChain100Setup::CreateValidTransaction(const std::vector<CTransactionRef>& input_transactions,

                                                                                  const std::vector<COutPoint>& inputs,

                                                                                  int input_height,

                                                                                  const std::vector<CKey>& input_signing_keys,

                                                                                  const std::vector<CTxOut>& outputs,

                                                                                  const std::optional<CFeeRate>& feerate,

                                                                                  const std::optional<uint32_t>& fee_output)

{

    CMutableTransaction mempool_txn;

    mempool_txn.vin.reserve(inputs.size());

    mempool_txn.vout.reserve(outputs.size());

    for (const auto& outpoint : inputs) {

        mempool_txn.vin.emplace_back(outpoint, CScript(), MAX_BIP125_RBF_SEQUENCE);

    }

    mempool_txn.vout = outputs;

    // - Add the signing key to a keystore

    FillableSigningProvider keystore;

    for (const auto& input_signing_key : input_signing_keys) {

        keystore.AddKey(input_signing_key);

    }

    // - Populate a CoinsViewCache with the unspent output

    CCoinsView coins_view;

    CCoinsViewCache coins_cache(&coins_view);

    for (const auto& input_transaction : input_transactions) {

        AddCoins(coins_cache, *input_transaction.get(), input_height);

    }

    // Build Outpoint to Coin map for SignTransaction

    std::map<COutPoint, Coin> input_coins;

    CAmount inputs_amount{0};

    for (const auto& outpoint_to_spend : inputs) {

        // Use GetCoin to properly populate utxo_to_spend

        auto utxo_to_spend{coins_cache.GetCoin(outpoint_to_spend).value()};

        input_coins.insert({outpoint_to_spend, utxo_to_spend});

        inputs_amount += utxo_to_spend.out.nValue;

    }

    // - Default signature hashing type

    int nHashType = SIGHASH_ALL;

    std::map<int, bilingual_str> input_errors;

    assert(SignTransaction(mempool_txn, &keystore, input_coins, nHashType, input_errors));

    CAmount current_fee = inputs_amount - std::accumulate(outputs.begin(), outputs.end(), CAmount(0),

        [](const CAmount& acc, const CTxOut& out) {

        return acc + out.nValue;

    });

    // Deduct fees from fee_output to meet feerate if set

    if (feerate.has_value()) {

        assert(fee_output.has_value());

        assert(fee_output.value() < mempool_txn.vout.size());

        CAmount target_fee = feerate.value().GetFee(GetVirtualTransactionSize(CTransaction{mempool_txn}));

        CAmount deduction = target_fee - current_fee;

        if (deduction > 0) {

            // Only deduct fee if there's anything to deduct. If the caller has put more fees than

            // the target feerate, don't change the fee.

            mempool_txn.vout[fee_output.value()].nValue -= deduction;

            // Re-sign since an output has changed

            input_errors.clear();

            assert(SignTransaction(mempool_txn, &keystore, input_coins, nHashType, input_errors));

            current_fee = target_fee;

        }

    }

    return {mempool_txn, current_fee};

}

CMutableTransaction TestChain100Setup::CreateValidMempoolTransaction(const std::vector<CTransactionRef>& input_transactions,

                                                                     const std::vector<COutPoint>& inputs,

                                                                     int input_height,

                                                                     const std::vector<CKey>& input_signing_keys,

                                                                     const std::vector<CTxOut>& outputs,

                                                                     bool submit)

{

    CMutableTransaction mempool_txn = CreateValidTransaction(input_transactions, inputs, input_height, input_signing_keys, outputs, std::nullopt, std::nullopt).first;

    // If submit=true, add transaction to the mempool.

    if (submit) {

        LOCK(cs_main);

        const MempoolAcceptResult result = m_node.chainman->ProcessTransaction(MakeTransactionRef(mempool_txn));

        assert(result.m_result_type == MempoolAcceptResult::ResultType::VALID);

    }

    return mempool_txn;

}

CMutableTransaction TestChain100Setup::CreateValidMempoolTransaction(CTransactionRef input_transaction,

                                                                     uint32_t input_vout,

                                                                     int input_height,

                                                                     CKey input_signing_key,

                                                                     CScript output_destination,

                                                                     CAmount output_amount,

                                                                     bool submit)

{

    COutPoint input{input_transaction->GetHash(), input_vout};

    CTxOut output{output_amount, output_destination};

    return CreateValidMempoolTransaction(/*input_transactions=*/{input_transaction},

                                         /*inputs=*/{input},

                                         /*input_height=*/input_height,

                                         /*input_signing_keys=*/{input_signing_key},

                                         /*outputs=*/{output},

                                         /*submit=*/submit);

}

std::vector<CTransactionRef> TestChain100Setup::PopulateMempool(FastRandomContext& det_rand, size_t num_transactions, bool submit)

{

    std::vector<CTransactionRef> mempool_transactions;

    std::deque<std::pair<COutPoint, CAmount>> unspent_prevouts;

    std::transform(m_coinbase_txns.begin(), m_coinbase_txns.end(), std::back_inserter(unspent_prevouts),

        [](const auto& tx){ return std::make_pair(COutPoint(tx->GetHash(), 0), tx->vout[0].nValue); });

    while (num_transactions > 0 && !unspent_prevouts.empty()) {

        // The number of inputs and outputs are random, between 1 and 24.

        CMutableTransaction mtx = CMutableTransaction();

        const size_t num_inputs = det_rand.randrange(24) + 1;

        CAmount total_in{0};

        for (size_t n{0}; n < num_inputs; ++n) {

            if (unspent_prevouts.empty()) break;

            const auto& [prevout, amount] = unspent_prevouts.front();

            mtx.vin.emplace_back(prevout, CScript());

            total_in += amount;

            unspent_prevouts.pop_front();

        }

        const size_t num_outputs = det_rand.randrange(24) + 1;

        const CAmount fee = 100 * det_rand.randrange(30);

        const CAmount amount_per_output = (total_in - fee) / num_outputs;

        for (size_t n{0}; n < num_outputs; ++n) {

            CScript spk = CScript() << CScriptNum(num_transactions + n);

            mtx.vout.emplace_back(amount_per_output, spk);

        }

        CTransactionRef ptx = MakeTransactionRef(mtx);

        mempool_transactions.push_back(ptx);

        if (amount_per_output > 3000) {

            // If the value is high enough to fund another transaction + fees, keep track of it so

            // it can be used to build a more complex transaction graph. Insert randomly into

            // unspent_prevouts for extra randomness in the resulting structures.

            for (size_t n{0}; n < num_outputs; ++n) {

                unspent_prevouts.emplace_back(COutPoint(ptx->GetHash(), n), amount_per_output);

                std::swap(unspent_prevouts.back(), unspent_prevouts[det_rand.randrange(unspent_prevouts.size())]);

            }

        }

        if (submit) {

            LOCK2(cs_main, m_node.mempool->cs);

            LockPoints lp;

            auto changeset = m_node.mempool->GetChangeSet();

            changeset->StageAddition(ptx, /*fee=*/(total_in - num_outputs * amount_per_output),

                    /*time=*/0, /*entry_height=*/1, /*entry_sequence=*/0,

                    /*spends_coinbase=*/false, /*sigops_cost=*/4, lp);

            changeset->Apply();

        }

        --num_transactions;

    }

    return mempool_transactions;

}

void TestChain100Setup::MockMempoolMinFee(const CFeeRate& target_feerate)

{

    LOCK2(cs_main, m_node.mempool->cs);

    // Transactions in the mempool will affect the new minimum feerate.

    assert(m_node.mempool->size() == 0);

    // The target feerate cannot be too low...

    // ...otherwise the transaction's feerate will need to be negative.

    assert(target_feerate > m_node.mempool->m_opts.incremental_relay_feerate);

    // ...otherwise this is not meaningful. The feerate policy uses the maximum of both feerates.

    assert(target_feerate > m_node.mempool->m_opts.min_relay_feerate);

    // Manually create an invalid transaction. Manually set the fee in the CTxMemPoolEntry to

    // achieve the exact target feerate.

    CMutableTransaction mtx = CMutableTransaction();

    mtx.vin.emplace_back(COutPoint{Txid::FromUint256(m_rng.rand256()), 0});

    mtx.vout.emplace_back(1 * COIN, GetScriptForDestination(WitnessV0ScriptHash(CScript() << OP_TRUE)));

    // Set a large size so that the fee evaluated at target_feerate (which is usually in sats/kvB) is an integer.

    // Otherwise, GetMinFee() may end up slightly different from target_feerate.

    BulkTransaction(mtx, 4000);

    const auto tx{MakeTransactionRef(mtx)};

    LockPoints lp;

    // The new mempool min feerate is equal to the removed package's feerate + incremental feerate.

    const auto tx_fee = target_feerate.GetFee(GetVirtualTransactionSize(*tx)) -

        m_node.mempool->m_opts.incremental_relay_feerate.GetFee(GetVirtualTransactionSize(*tx));

    {

        auto changeset = m_node.mempool->GetChangeSet();

        changeset->StageAddition(tx, /*fee=*/tx_fee,

                /*time=*/0, /*entry_height=*/1, /*entry_sequence=*/0,

                /*spends_coinbase=*/true, /*sigops_cost=*/1, lp);

        changeset->Apply();

    }

    m_node.mempool->TrimToSize(0);

    assert(m_node.mempool->GetMinFee() == target_feerate);

}

/**

 * @returns a real block (0000000000013b8ab2cd513b0261a14096412195a72a0c4827d229dcc7e0f7af)

 *      with 9 txs.

 */

CBlock getBlock13b8a()

{

    CBlock block;

    DataStream stream{

        "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"_hex,

    };

    stream >> TX_WITH_WITNESS(block);

    return block;

}

std::ostream& operator<<(std::ostream& os, const arith_uint256& num)

{

    return os << num.ToString();

}

std::ostream& operator<<(std::ostream& os, const uint160& num)

{

    return os << num.ToString();

}

std::ostream& operator<<(std::ostream& os, const uint256& num)

{

    return os << num.ToString();

}

std::ostream& operator<<(std::ostream& os, const Txid& txid) {

    return os << txid.ToString();

}

std::ostream& operator<<(std::ostream& os, const Wtxid& wtxid) {

    return os << wtxid.ToString();

}