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test_cold_account_access_at_transition()

Documentation for tests/amsterdam/eip8038_state_access_gas_cost_increase/test_fork_transition.py::test_cold_account_access_at_transition@343274cc.

Generate fixtures for these test cases for Amsterdam with:

fill -v tests/amsterdam/eip8038_state_access_gas_cost_increase/test_fork_transition.py::test_cold_account_access_at_transition --fork Amsterdam

BALANCE of a cold account costs COLD_ACCOUNT_ACCESS, which rises across the Amsterdam boundary. The same opcode is measured before and after; each block asserts its regime's derived cost.

Source code in tests/amsterdam/eip8038_state_access_gas_cost_increase/test_fork_transition.py 
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@EIPChecklist.GasCostChanges.Test.ForkTransition.Before()
@EIPChecklist.GasCostChanges.Test.ForkTransition.After()
def test_cold_account_access_at_transition(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    fork: Fork,
) -> None:
    """
    ``BALANCE`` of a cold account costs ``COLD_ACCOUNT_ACCESS``, which
    rises across the Amsterdam boundary. The
    same opcode is measured before and after; each block asserts its
    regime's derived cost.
    """
    before = fork.fork_at(timestamp=BEFORE_TS)
    after = fork.fork_at(timestamp=AFTER_TS)

    # BALANCE's bare cost equals COLD_ACCOUNT_ACCESS in each regime.
    cold_balance = Op.BALANCE.with_metadata(address_warm=False)
    cost_before = cold_balance.gas_cost(before)
    cost_after = cold_balance.gas_cost(after)
    assert cost_after > cost_before

    target = pre.deploy_contract(code=Op.STOP)

    # A distinct cold target per block keeps each measurement cold.
    target_after = pre.deploy_contract(code=Op.STOP)

    # BALANCE has no code-read surcharge, so its bare cost equals
    # COLD_ACCOUNT_ACCESS in each regime.
    measure_before = _measure_contract(
        pre, Op.BALANCE(target), cost_before, before
    )
    measure_after = _measure_contract(
        pre, Op.BALANCE(target_after), cost_after, after
    )

    blocks = transition_blocks(measure_before, measure_after, pre)

    post = {
        measure_before: Account(storage={0: cost_before}),
        measure_after: Account(storage={0: cost_after}),
    }
    blockchain_test(pre=pre, blocks=blocks, post=post)

Parametrized Test Cases

This test generates 1 parametrized test case across 1 fork.