def test_overlap_integrals_are_consistent():
    a = Material(1.0, 0.0, 1.0, 1.0, 1.0)
    b = Material(1.0, -0.5, 1.0, 1.0, 1.0)  # Lower band edges.
    csnc1 = CoreShellParticle(a, b, 1.0, 1.0)  # Type 2 CSNC. h/e structure.
    assert np.isclose(csnc1.analytical_overlap_integral(),
                      csnc1.numerical_overlap_integral())
def test_numerical_overlap_integral_is_at_or_below_one():
    a = Material(1.0, 0.0, 1.0, 1.0, 1.0)
    b = Material(1.0, -0.5, 1.0, 1.0, 1.0)  # Lower band edges.
    csnc1 = CoreShellParticle(a, b, 1.0, 1.0)  # Type 2 CSNC. h/e structure.
    assert csnc1.numerical_overlap_integral() <= 1.0