test_invalid_negative_excess_blob_gas()

Documentation for tests/cancun/eip4844_blobs/test_excess_blob_gas.py::test_invalid_negative_excess_blob_gas@892e6d1e.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/cancun/eip4844_blobs/test_excess_blob_gas.py::test_invalid_negative_excess_blob_gas --fork Amsterdam

Test rejection of blocks where the excessBlobGas changes to the two's complement equivalent of the negative value after subtracting target blobs.

Reasoning is that the excessBlobGas is a uint64, so it cannot be negative, and we test for a potential underflow here.

Source code in tests/cancun/eip4844_blobs/test_excess_blob_gas.py

@pytest.mark.parametrize_by_fork(
    "header_excess_blob_gas",
    lambda fork: [
        (2**64 + (x * fork.blob_gas_per_blob()))
        for x in range(-fork.target_blobs_per_block(), 0)
    ],
)
@pytest.mark.parametrize_by_fork(
    "parent_blobs",
    lambda fork: range(fork.target_blobs_per_block()),
)
@pytest.mark.parametrize("new_blobs", [1])
@pytest.mark.parametrize_by_fork(
    "parent_excess_blobs",
    lambda fork: range(fork.target_blobs_per_block()),
)
@pytest.mark.exception_test
@pytest.mark.slow()
def test_invalid_negative_excess_blob_gas(
    blockchain_test: BlockchainTestFiller,
    env: Environment,
    pre: Mapping[Address, Account],
    blocks: List[Block],
    correct_excess_blob_gas: int,
    header_excess_blob_gas: Optional[int],
) -> None:
    """
    Test rejection of blocks where the `excessBlobGas` changes to the two's
    complement equivalent of the negative value after subtracting target blobs.

    Reasoning is that the `excessBlobGas` is a `uint64`, so it cannot be
    negative, and we test for a potential underflow here.
    """
    if header_excess_blob_gas is None:
        raise Exception("test case is badly formatted")

    if header_excess_blob_gas == correct_excess_blob_gas:
        raise Exception("invalid test case")

    blockchain_test(
        pre=pre,
        post={},
        blocks=blocks,
        genesis_environment=env,
    )

Parametrized Test Cases

This test generates 2744 parametrized test cases across 4 forks.