import time
from idea157_openfederatedcompiler_privacy_preserving import LocalPolicy, PlanDelta, DeltaEngine


def test_basic_delta_merge_updates_local_policy():
    lp = LocalPolicy(id="lp1", device_type="drone", objective="limit_latency", constraints={"latency_ms": 50})
    delta = PlanDelta(delta={"objective": "reduce_latency", "constraints": {"latency_ms": 30}}, author="tester", contract_id="c1")

    updated = DeltaEngine.merge(lp, delta)

    assert updated.objective == "reduce_latency"
    assert updated.constraints["latency_ms"] == 30
    # Ensure other fields persist
    assert updated.id == "lp1"
    assert updated.device_type == "drone"