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test_swapn_pc_advances_by_2()

Documentation for tests/amsterdam/eip8024_dupn_swapn_exchange/test_pc_advancement.py::test_swapn_pc_advances_by_2@9c2813ee.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8024_dupn_swapn_exchange/test_pc_advancement.py::test_swapn_pc_advances_by_2 --fork Amsterdam

Verify PC advances by 2 after SWAPN (opcode + immediate byte).

Tests that SWAPN consumes the immediate byte and advances PC correctly.

Source code in tests/amsterdam/eip8024_dupn_swapn_exchange/test_pc_advancement.py 
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def test_swapn_pc_advances_by_2(
    pre: Alloc,
    state_test: StateTestFiller,
) -> None:
    """
    Verify PC advances by 2 after SWAPN (opcode + immediate byte).

    Tests that SWAPN consumes the immediate byte and advances PC correctly.
    """
    sender = pre.fund_eoa()

    code = Bytecode()

    # Push 18 values so SWAPN[17] will work (needs 18 items on stack)
    for i in range(18):
        code += Op.PUSH1(i)

    # Capture PC before SWAPN and store it
    code += Op.PC
    code += Op.PUSH1(1) + Op.SSTORE

    # Execute SWAPN - should advance PC by 2 (opcode + immediate)
    code += Op.SWAPN[17]

    # Capture PC after SWAPN and store it
    code += Op.PC
    code += Op.PUSH1(2) + Op.SSTORE

    # Calculate difference
    code += Op.PUSH1(1) + Op.SLOAD  # Load PC_before
    code += Op.PUSH1(2) + Op.SLOAD  # Load PC_after
    code += Op.SUB  # PC_after - PC_before

    # Store the difference
    code += Op.PUSH1(0) + Op.SSTORE

    # Clean up intermediate storage
    code += Op.PUSH1(0) + Op.PUSH1(1) + Op.SSTORE  # Clear key 1
    code += Op.PUSH1(0) + Op.PUSH1(2) + Op.SSTORE  # Clear key 2

    code += Op.STOP

    contract_address = pre.deploy_contract(code=code)
    tx = Transaction(to=contract_address, sender=sender, gas_limit=1_000_000)

    post = {
        contract_address: Account(
            storage={
                0: 6,  # PUSH1(2) + SSTORE(1) + SWAPN(2) + PC(1) = 6
            }
        )
    }

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

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.