test_bal_gas_limit_boundary()

Documentation for tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists.py::test_bal_gas_limit_boundary@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists.py::test_bal_gas_limit_boundary --fork Amsterdam

BAL max-items cap (bal_items <= block_gas_limit // BLOCK_ACCESS_LIST_ITEM) must be enforced on the final BAL — including pre-tx system work (beacon root, history), user txs, and post-tx system work (CL withdrawals, queue processing).

Orthogonal axes: - with_tx: alice → bob transfer adds 3 items (alice + bob + coinbase warmed via EIP-3651). - with_cl_withdrawal: EIP-4895 withdrawal to a recipient adds 1 item, processed between txs and the rest of the post-tx system work. Together they catch clients that validate the cap before process_withdrawals runs.

Source code in tests/amsterdam/eip7928_block_level_access_lists/test_block_access_lists.py

@EIPChecklist.BlockLevelConstraint.Test.Boundary.Under()
@EIPChecklist.BlockLevelConstraint.Test.Boundary.Exact()
@EIPChecklist.BlockLevelConstraint.Test.Boundary.Over()
@pytest.mark.parametrize(
    "with_cl_withdrawal",
    [
        pytest.param(False, id="no_cl_withdrawal"),
        pytest.param(True, id="with_cl_withdrawal"),
    ],
)
@pytest.mark.parametrize(
    "with_tx",
    [pytest.param(False, id="no_tx"), pytest.param(True, id="with_tx")],
)
@pytest.mark.parametrize(
    "boundary_offset",
    [
        pytest.param(0, id="at_boundary"),
        pytest.param(
            -1, marks=pytest.mark.exception_test, id="below_boundary"
        ),
    ],
)
def test_bal_gas_limit_boundary(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    fork: Fork,
    boundary_offset: int,
    with_tx: bool,
    with_cl_withdrawal: bool,
) -> None:
    """
    BAL max-items cap (``bal_items <= block_gas_limit //
    BLOCK_ACCESS_LIST_ITEM``) must be enforced on the **final** BAL —
    including pre-tx system work (beacon root, history), user txs, and
    post-tx system work (CL withdrawals, queue processing).

    Orthogonal axes:
    - `with_tx`: alice → bob transfer adds 3 items (alice + bob +
      coinbase warmed via EIP-3651).
    - `with_cl_withdrawal`: EIP-4895 withdrawal to a recipient adds 1
      item, processed between txs and the rest of the post-tx system
      work. Together they catch clients that validate the cap before
      `process_withdrawals` runs.
    """
    # Match framework's DEFAULT_BASE_FEE so gas_price == base_fee
    # cancels the priority fee (no coinbase balance_change to absorb
    # into the expected counts).
    base_fee_per_gas = 7

    extra_items = 0
    txs: list = []
    withdrawals: list = []
    expected_accounts: dict = {}
    post: dict = {}

    if with_tx:
        alice = pre.fund_eoa()
        # Fund bob with 1 wei so the recipient is alive at top-frame
        # check time; this avoids the EIP-2780 ``NEW_ACCOUNT`` state
        # charge that would otherwise inflate the tx's gas needs past
        # the BAL-sized ``block_gas_limit``.
        bob = pre.fund_eoa(amount=1)
        # alice (sender) + bob (recipient) + coinbase (EIP-3651 warm).
        extra_items += 3
        txs.append(
            Transaction(
                sender=alice,
                to=bob,
                value=1,
                gas_price=base_fee_per_gas,
            )
        )
        expected_accounts[alice] = BalAccountExpectation(
            nonce_changes=[BalNonceChange(block_access_index=1, post_nonce=1)],
        )
        expected_accounts[bob] = BalAccountExpectation(
            balance_changes=[
                BalBalanceChange(block_access_index=1, post_balance=2)
            ],
        )
        post[bob] = Account(balance=2)

    if with_cl_withdrawal:
        charlie = pre.fund_eoa(amount=0)
        withdrawal_amount_wei = 10**9  # 1 gwei
        # CL withdrawal recipient adds 1 item; processed at
        # block_access_index = len(txs) + 1 (post-tx).
        extra_items += 1
        withdrawals.append(
            Withdrawal(index=0, validator_index=0, address=charlie, amount=1)
        )
        expected_accounts[charlie] = BalAccountExpectation(
            balance_changes=[
                BalBalanceChange(
                    block_access_index=len(txs) + 1,
                    post_balance=withdrawal_amount_wei,
                )
            ],
        )
        post[charlie] = Account(balance=withdrawal_amount_wei)

    total_items = fork.empty_block_bal_item_count() + extra_items
    gas_limit = (
        total_items * fork.gas_costs().BLOCK_ACCESS_LIST_ITEM + boundary_offset
    )

    at_boundary = boundary_offset == 0
    block = Block(
        txs=txs,
        withdrawals=withdrawals,
        exception=(
            None
            if at_boundary
            else BlockException.BLOCK_ACCESS_LIST_GAS_LIMIT_EXCEEDED
        ),
        expected_block_access_list=(
            BlockAccessListExpectation(account_expectations=expected_accounts)
            if at_boundary and expected_accounts
            else None
        ),
    )

    blockchain_test(
        pre=pre,
        blocks=[block],
        post=post if at_boundary else {},
        genesis_environment=Environment(
            base_fee_per_gas=base_fee_per_gas, gas_limit=gas_limit
        ),
    )

Parametrized Test Cases

This test generates 8 parametrized test cases across 1 fork.