test_block_hashes_history()

Documentation for tests/prague/eip2935_historical_block_hashes_from_state/test_block_hashes.py::test_block_hashes_history@20373115.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/prague/eip2935_historical_block_hashes_from_state/test_block_hashes.py::test_block_hashes_history --fork Amsterdam

Tests that block hashes are stored correctly at the system contract address after the fork transition. Block hashes are stored incrementally at the transition until the HISTORY_SERVE_WINDOW ring buffer is full. Afterwards the oldest block hash is replaced by the new one.

Source code in tests/prague/eip2935_historical_block_hashes_from_state/test_block_hashes.py

@pytest.mark.parametrize(
    "block_count,check_contract_first",
    [
        pytest.param(1, False, id="single_block_check_blockhash_first"),
        pytest.param(1, True, id="single_block_check_contract_first"),
        pytest.param(2, False, id="two_blocks_check_blockhash_first"),
        pytest.param(2, True, id="two_blocks_check_contract_first"),
        pytest.param(
            Spec.HISTORY_SERVE_WINDOW + 1,
            False,
            marks=[
                pytest.mark.skip("Slow test not relevant anymore"),
                pytest.mark.slow,
            ],
            id="full_history_plus_one_check_blockhash_first",
        ),
    ],
)
@pytest.mark.valid_from("Prague")
@pytest.mark.eels_base_coverage
def test_block_hashes_history(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    block_count: int,
    check_contract_first: bool,
) -> None:
    """
    Tests that block hashes are stored correctly at the system contract address
    after the fork transition. Block hashes are stored incrementally at the
    transition until the `HISTORY_SERVE_WINDOW` ring buffer is full. Afterwards
    the oldest block hash is replaced by the new one.
    """
    blocks: List[Block] = []

    sender = pre.fund_eoa(10_000_000_000)
    post: Dict[Address, Account] = {}
    current_block_number = 1
    fork_block_number = 0  # We fork at genesis

    for _ in range(block_count - 1):
        # Generate empty blocks after the fork.
        blocks.append(Block())
        current_block_number += 1

    txs = []
    # On these blocks, `BLOCKHASH` will still return values for the last 256
    # blocks, and `HISTORY_STORAGE_ADDRESS` should now serve values for the
    # previous blocks in the new fork.
    code = Bytecode()
    storage = Storage()

    # Check the first block outside of the window if any
    code += generate_block_check_code(
        check_block_number=current_block_number
        - Spec.HISTORY_SERVE_WINDOW
        - 1,
        current_block_number=current_block_number,
        fork_block_number=fork_block_number,
        storage=storage,
        check_contract_first=check_contract_first,
    )

    # Check the first block inside the window
    code += generate_block_check_code(
        check_block_number=current_block_number - Spec.HISTORY_SERVE_WINDOW,
        current_block_number=current_block_number,
        fork_block_number=fork_block_number,
        storage=storage,
        check_contract_first=check_contract_first,
    )

    # Check the first block outside the BLOCKHASH window
    code += generate_block_check_code(
        check_block_number=current_block_number
        - Spec.BLOCKHASH_OLD_WINDOW
        - 1,
        current_block_number=current_block_number,
        fork_block_number=fork_block_number,
        storage=storage,
        check_contract_first=check_contract_first,
    )

    # Check the first block inside the BLOCKHASH window
    code += generate_block_check_code(
        check_block_number=current_block_number - Spec.BLOCKHASH_OLD_WINDOW,
        current_block_number=current_block_number,
        fork_block_number=fork_block_number,
        storage=storage,
        check_contract_first=check_contract_first,
    )

    # Check the previous block
    code += generate_block_check_code(
        check_block_number=current_block_number - 1,
        current_block_number=current_block_number,
        fork_block_number=fork_block_number,
        storage=storage,
        check_contract_first=check_contract_first,
    )

    check_blocks_after_fork_address = pre.deploy_contract(code)
    txs.append(
        Transaction(
            to=check_blocks_after_fork_address,
            gas_limit=10_000_000,
            sender=sender,
        )
    )
    post[check_blocks_after_fork_address] = Account(storage=storage)

    blocks.append(Block(txs=txs))
    current_block_number += 1

    blockchain_test(
        pre=pre,
        blocks=blocks,
        post=post,
    )

Parametrized Test Cases

This test generates 5 parametrized test cases across 3 forks.