test_maximum_gas_refund()

Documentation for tests/osaka/eip7825_transaction_gas_limit_cap/test_tx_gas_limit.py::test_maximum_gas_refund@892e6d1e.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/osaka/eip7825_transaction_gas_limit_cap/test_tx_gas_limit.py::test_maximum_gas_refund --fork Amsterdam

Test the maximum gas refund behavior according to EIP-3529.

Source code in tests/osaka/eip7825_transaction_gas_limit_cap/test_tx_gas_limit.py

@pytest.mark.parametrize(
    "exceed_gas_refund_limit",
    [
        pytest.param(True),
        pytest.param(False),
    ],
)
@pytest.mark.valid_from("Osaka")
def test_maximum_gas_refund(
    state_test: StateTestFiller,
    pre: Alloc,
    fork: Fork,
    exceed_gas_refund_limit: bool,
) -> None:
    """Test the maximum gas refund behavior according to EIP-3529."""
    gas_costs = fork.gas_costs()
    tx_gas_limit_cap = fork.transaction_gas_limit_cap()
    assert tx_gas_limit_cap is not None, (
        "Fork does not have a transaction gas limit cap"
    )
    max_refund_quotient = fork.max_refund_quotient()

    storage = Storage()

    # Base Operation: SSTORE(slot, 0)
    iteration_cost = (
        Op.SSTORE(key_warm=True, original_value=1, new_value=0)
        + Op.PUSH0
        + Op.PUSH1(0)
    ).gas_cost(fork)
    gas_refund = gas_costs.REFUND_STORAGE_CLEAR

    # EIP-3529: Reduction in refunds
    storage_count = tx_gas_limit_cap // iteration_cost
    gas_used = storage_count * iteration_cost

    maximum_gas_refund = gas_used // max_refund_quotient
    gas_refund_count = maximum_gas_refund // gas_refund

    # Base case: operations that fit within the refund limit
    iteration_count = min(
        storage_count, gas_refund_count + int(exceed_gas_refund_limit)
    )

    assert iteration_cost * iteration_count <= tx_gas_limit_cap, (
        "Iteration cost exceeds tx gas limit cap"
    )

    opcode = sum(
        (
            Op.SSTORE(storage.store_next(0), Op.PUSH0)
            for _ in range(iteration_count)
        ),
        Bytecode(),
    )
    assert len(opcode) <= fork.max_code_size(), (
        "code size exceeds max code size"
    )

    contract = pre.deploy_contract(
        code=opcode,
        storage={Hash(i): Hash(1) for i in range(iteration_count)},
    )

    tx = Transaction(
        to=contract,
        sender=pre.fund_eoa(),
        gas_limit=tx_gas_limit_cap,
    )

    post = {contract: Account(storage=storage)}

    state_test(pre=pre, post=post, tx=tx)

Parametrized Test Cases

This test generates 2 parametrized test cases across 2 forks.