test_exchange_jump_to_immediate_byte()

Documentation for tests/amsterdam/eip8024_dupn_swapn_exchange/test_exchange.py::test_exchange_jump_to_immediate_byte@a9abd46e.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8024_dupn_swapn_exchange/test_exchange.py::test_exchange_jump_to_immediate_byte --fork Amsterdam

Test jumping to EXCHANGE immediate byte position.

Valid immediates are skipped (can't jump to them). Invalid immediates are not skipped - only 0x5B (JUMPDEST) allows jumping.

Source code in tests/amsterdam/eip8024_dupn_swapn_exchange/test_exchange.py

@pytest.mark.parametrize(
    "immediate",
    [
        # valid immediates (0-81 / 128-255): skipped during JUMPDEST
        # analysis, not reachable as jump targets
        0x00,
        0x4F,  # 79
        0x50,  # 80 — POP (valid for EXCHANGE)
        0x51,  # 81 — MLOAD (valid for EXCHANGE)
        # invalid immediates (82-127): not skipped during JUMPDEST
        # analysis, only 0x5B (91) is a JUMPDEST
        0x52,  # 82 — MSTORE (first invalid immediate)
        0x5A,  # 90 — GAS (invalid immediate)
        0x5B,  # 91 — JUMPDEST, only case where jump succeeds
        0x5C,  # 92 — TLOAD (invalid immediate)
        0x60,  # 96 — PUSH1 (invalid immediate)
        0x7F,  # 127 — PUSH32 (last invalid immediate)
        # valid immediates again (128-255)
        0x80,  # 128
        0xFF,  # 255
    ],
    ids=lambda x: f"imm_0x{x:02x}",
)
def test_exchange_jump_to_immediate_byte(
    immediate: int,
    pre: Alloc,
    state_test: StateTestFiller,
) -> None:
    """
    Test jumping to EXCHANGE immediate byte position.

    Valid immediates are skipped (can't jump to them).
    Invalid immediates are not skipped - only 0x5B (JUMPDEST) allows jumping.
    """
    sender = pre.fund_eoa()

    # Bytecode: PUSH1(4) JUMP EXCHANGE[imm] - position 4 is the immediate byte
    code = Bytecode()
    code += Op.PUSH1(4)
    code += Op.JUMP
    code += Op.EXCHANGE[immediate.to_bytes(1, "big")]

    code += Op.PUSH1(0x42) + Op.PUSH1(0) + Op.SSTORE
    code += Op.STOP

    contract_address = pre.deploy_contract(code=code)
    tx = Transaction(to=contract_address, sender=sender)

    if immediate == 0x5B:  # JUMPDEST - only case where jump succeeds
        post = {contract_address: Account(storage={0: 0x42})}
    else:
        post = {contract_address: Account(storage={})}

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

Parametrized Test Cases

This test generates 12 parametrized test cases across 1 fork.