Method TestPackageSelection

src/test/miner_tests.cpp:132–300

Test suite for ancestor feerate transaction selection. Implemented as an additional function, rather than a separate test case, to allow reusing the blockchain created in CreateNewBlock_validity.

// Implemented as an additional function, rather than a separate test case,
// to allow reusing the blockchain created in CreateNewBlock_validity.
void MinerTestingSetup::TestPackageSelection(const CScript& scriptPubKey, const std::vector<CTransactionRef>& txFirst)
{
    CTxMemPool& tx_mempool{MakeMempool()};
    auto mining{MakeMining()};
    BlockCreateOptions options{
        .coinbase_output_script = scriptPubKey,
    };

    LOCK(tx_mempool.cs);
    BOOST_CHECK(tx_mempool.size() == 0);

    // Block template should only have a coinbase when there's nothing in the mempool
    std::unique_ptr<BlockTemplate> block_template = mining->createNewBlock(options, /*cooldown=*/false);
    BOOST_REQUIRE(block_template);
    CBlock block{block_template->getBlock()};
    BOOST_REQUIRE_EQUAL(block.vtx.size(), 1U);

    // waitNext() on an empty mempool should return nullptr because there is no better template
    auto should_be_nullptr = block_template->waitNext({.timeout = MillisecondsDouble{0}, .fee_threshold = 1});
    BOOST_REQUIRE(should_be_nullptr == nullptr);

    // Unless fee_threshold is 0
    block_template = block_template->waitNext({.timeout = MillisecondsDouble{0}, .fee_threshold = 0});
    BOOST_REQUIRE(block_template);

    // Test the ancestor feerate transaction selection.
    TestMemPoolEntryHelper entry;

    // Test that a medium fee transaction will be selected after a higher fee
    // rate package with a low fee rate parent.
    CMutableTransaction tx;
    tx.vin.resize(1);
    tx.vin[0].scriptSig = CScript() << OP_1;
    tx.vin[0].prevout.hash = txFirst[0]->GetHash();
    tx.vin[0].prevout.n = 0;
    tx.vout.resize(1);
    tx.vout[0].nValue = 5000000000LL - 1000;
    // This tx has a low fee: 1000 satoshis
    Txid hashParentTx = tx.GetHash(); // save this txid for later use
    const auto parent_tx{entry.Fee(1000).Time(Now<NodeSeconds>()).SpendsCoinbase(true).FromTx(tx)};
    TryAddToMempool(tx_mempool, parent_tx);

    // This tx has a medium fee: 10000 satoshis
    tx.vin[0].prevout.hash = txFirst[1]->GetHash();
    tx.vout[0].nValue = 5000000000LL - 10000;
    Txid hashMediumFeeTx = tx.GetHash();
    const auto medium_fee_tx{entry.Fee(10000).Time(Now<NodeSeconds>()).SpendsCoinbase(true).FromTx(tx)};
    TryAddToMempool(tx_mempool, medium_fee_tx);

    // This tx has a high fee, but depends on the first transaction
    tx.vin[0].prevout.hash = hashParentTx;
    tx.vout[0].nValue = 5000000000LL - 1000 - 50000; // 50k satoshi fee
    Txid hashHighFeeTx = tx.GetHash();
    const auto high_fee_tx{entry.Fee(50000).Time(Now<NodeSeconds>()).SpendsCoinbase(false).FromTx(tx)};
    TryAddToMempool(tx_mempool, high_fee_tx);

    block_template = mining->createNewBlock(options, /*cooldown=*/false);
    BOOST_REQUIRE(block_template);