test_slotnum_distinct_per_block()¶

@EIPChecklist.Opcode.Test.ExecutionContext.BlockContext()
@EIPChecklist.BlockHeaderField.Test.ValueBehavior.Accept()
def test_slotnum_distinct_per_block(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
) -> None:
    """
    Test that SLOTNUM returns each block's own slot number.

    Runs four consecutive blocks with deliberately non-monotonic slot
    numbers to disprove any caching or ordering assumption in the opcode
    implementation. Each block runs the same contract, which keys storage
    by block ``NUMBER`` so every block's outcome is independently visible
    in the final post-state.
    """
    sender = pre.fund_eoa()
    contract = pre.deploy_contract(Op.SSTORE(Op.NUMBER, Op.SLOTNUM) + Op.STOP)

    # Non-monotonic on purpose: decrease, increase, jump to large value.
    slot_numbers = [100, 42, 7, 2**32]

    blocks = [
        Block(
            slot_number=slot,
            txs=[Transaction(sender=sender, to=contract)],
        )
        for slot in slot_numbers
    ]

    post = {
        contract: Account(
            storage={i + 1: slot for i, slot in enumerate(slot_numbers)},
        ),
    }

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