import pytest

from gridresilience_studio.core import Object, Morphism, PlanDelta, DeltaStore
from gridresilience_studio.offline_sync import DeltaSyncEngine


def test_build_sample_world_and_delta_sync_basic():
    # Build a tiny world and ensure delta can be applied and snapshot produced
    ds = DeltaStore()
    ds.add_object(Object(id="DER1", type="DER", properties={"rated_kW": 500}))
    ds.add_object(Object(id="LOAD1", type="Load", properties={"critical": True}))
    ds.add_morphism(Morphism(id="SIG1", source="DER1", target="LOAD1", signals={"voltage": 1.0}))
    delta = PlanDelta(delta_id="D1", islanded=True, actions=[{"type": "island", "target": "LOAD1"}])
    ds.add_delta(delta)

    engine = DeltaSyncEngine(store=ds)
    engine.apply_delta(delta)
    snap = engine.snapshot()

    assert len(snap) == 1
    assert snap[0].delta_id == "D1"