from __future__ import annotations

import numpy as np

from src import structural_validate_t2_models as module


def test_notched_bar_geometry_is_positive_and_symmetric() -> None:
    nodes, area = module.geometry(12)
    assert np.all(np.diff(nodes) > 0.0)
    assert np.all(area > 0.0)
    np.testing.assert_allclose(area, area[::-1])


def test_native_response_returns_positive_algorithmic_tangent() -> None:
    stress, tangent, state = module.native_response(module.material(), None, 0.003)
    assert np.isfinite(stress)
    assert tangent > 0.0
    assert state.equivalent_plastic_strain > 0.0


def test_load_history_contains_reversals() -> None:
    history = module.load_history(81)
    increments = np.diff(history)
    assert np.any(increments > 0.0)
    assert np.any(increments < 0.0)