from __future__ import annotations

from physix.systems.registry import (
    SUPPORTED_SYSTEMS,
    SYSTEM_REGISTRY,
    get_system,
    list_supported_systems,
)


def test_supported_systems_is_non_empty() -> None:
    assert len(SUPPORTED_SYSTEMS) > 0


def test_supported_systems_only_references_registered_systems() -> None:
    for system_id in SUPPORTED_SYSTEMS:
        assert system_id in SYSTEM_REGISTRY


def test_list_supported_systems_preserves_declared_order() -> None:
    assert list_supported_systems() == list(SUPPORTED_SYSTEMS)


def test_every_supported_system_instantiates_cleanly() -> None:
    for system_id in SUPPORTED_SYSTEMS:
        system = get_system(system_id)
        assert system.system_id == system_id
        assert system.state_variables, f"{system_id} declares no state variables"