test_block_hashes_history()

Documentation for tests/prague/eip2935_historical_block_hashes_from_state/test_block_hashes.py::test_block_hashes_history@49a16fac.

Generate fixtures for these test cases for Prague with:

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

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.slow,
            id="full_history_plus_one_check_blockhash_first",
        ),
    ],
)
@pytest.mark.valid_from("Prague")
def test_block_hashes_history(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    block_count: int,
    check_contract_first: bool,
):
    """
    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

The interactive table below is also available as a standalone page.

Fork All Forks Prague Osaka

Fixture Type All Fixture Types blockchain_test

Test ID (Abbreviated)	block_count	check_contract_first
...fork_Prague-blockchain_test-single_block_check_blockhash_first	1	False
...fork_Prague-blockchain_test-single_block_check_contract_first	1	True
...fork_Prague-blockchain_test-two_blocks_check_blockhash_first	2	False
...fork_Prague-blockchain_test-two_blocks_check_contract_first	2	True
...fork_Prague-blockchain_test-full_history_plus_one_check_blockhash_first	8192	False
...fork_Osaka-blockchain_test-single_block_check_blockhash_first	1	False
...fork_Osaka-blockchain_test-single_block_check_contract_first	1	True
...fork_Osaka-blockchain_test-two_blocks_check_blockhash_first	2	False
...fork_Osaka-blockchain_test-two_blocks_check_contract_first	2	True
...fork_Osaka-blockchain_test-full_history_plus_one_check_blockhash_first	8192	False