test_swapn_with_dup1_and_push()

Documentation for tests/amsterdam/eip8024_dupn_swapn_exchange/test_swapn.py::test_swapn_with_dup1_and_push@622620d8.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8024_dupn_swapn_exchange/test_swapn.py::test_swapn_with_dup1_and_push --fork Amsterdam

Test SWAPN swapping top and bottom after building stack with DUP1.

Stack layout: PUSH1(1) PUSH1(0) DUP1*15 PUSH1(2) SWAPN[0x80] Before SWAPN: [2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1] After SWAPN[0x80] (decode_single(0x80)=17, swaps pos 1 and 18): [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2] Result: 18 stack items, top=1, bottom=2, rest=0

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

def test_swapn_with_dup1_and_push(
    pre: Alloc,
    state_test: StateTestFiller,
) -> None:
    """
    Test SWAPN swapping top and bottom after building stack with DUP1.

    Stack layout: PUSH1(1) PUSH1(0) DUP1*15 PUSH1(2) SWAPN[0x80]
    Before SWAPN: [2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
    After SWAPN[0x80] (decode_single(0x80)=17, swaps pos 1 and 18):
    [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
    Result: 18 stack items, top=1, bottom=2, rest=0
    """
    sender = pre.fund_eoa()

    # Build the stack: PUSH1(1), PUSH1(0), 15x DUP1, PUSH1(2)
    code = Bytecode()
    code += Op.PUSH1(1)  # Position 18 after DUP1s and final PUSH1
    code += Op.PUSH1(0)
    for _ in range(15):
        code += Op.DUP1
    code += Op.PUSH1(2)  # Top of stack (position 1)

    # Stack: [2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]
    # SWAPN with immediate 0x80 (decode_single(0x80)=17) swaps pos 1 and 18
    # Pass as bytes (raw immediate byte for testing)
    code += Op.SWAPN[b"\x80"]

    # Store all stack values to verify
    for i in range(18):
        code += Op.PUSH1(i) + Op.SSTORE

    code += Op.STOP

    contract_address = pre.deploy_contract(code=code)

    tx = Transaction(to=contract_address, sender=sender)

    # Expected: top (position 0) = 1, bottom (position 17) = 2, rest = 0
    expected_storage = {}
    for i in range(18):
        if i == 0:
            expected_storage[i] = 1  # Was at bottom, now at top
        elif i == 17:
            expected_storage[i] = 2  # Was at top, now at bottom
        else:
            expected_storage[i] = 0  # All middle values

    post = {contract_address: Account(storage=expected_storage)}

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

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.