symclaw/crates/symclaw-materials/tests/integration.rs

//! Integration tests for symclaw-materials.
//!
//! Cross-module scenarios: lattice → groups → structure → bonding pipeline.

use std::collections::HashMap;
use symclaw_materials::bonding::{
    BondValence, LennardJones, MadelungStructure, pauling_electronegativity, pauling_ionicity,
};
use symclaw_materials::groups::{PointGroup, SpaceGroup, SymOp};
use symclaw_materials::lattice::{CrystalSystem, LatticeParameters, Miller};
use symclaw_materials::structure::{CrystalStructure, ScatteringFactor, structure_factor};

// ── Lattice → structure pipeline ──────────────────────────────────

#[test]
fn nacl_full_pipeline() {
    // Build structure → compute d-spacings → structure factors
    let nacl = CrystalStructure::nacl();
    let a = nacl.lattice.a;

    // (200) reflection allowed in Fm-3m
    let m200 = Miller::new(2, 0, 0);
    let d200 = m200.d_spacing_cubic(a);
    assert!(d200 > 0.0, "d(200) > 0");

    // Bragg angle for Cu Kα
    let two_theta = Miller::bragg_angle_deg(d200, 1.5406).unwrap();
    assert!(
        two_theta > 20.0 && two_theta < 40.0,
        "NaCl (200) Bragg angle should be 20-40°, got {two_theta:.1}°"
    );
}

#[test]
fn silicon_lattice_parameters() {
    let si = CrystalStructure::silicon();
    let vol = si.lattice.volume();
    // Si a=5.4309 Å → V = a³ ≈ 160.2 ų
    assert!(
        (vol - 160.2).abs() < 1.0,
        "Si unit cell V ≈ 160.2 ų, got {vol:.1}"
    );
}

#[test]
fn reciprocal_lattice_cubic_orthogonal() {
    // For cubic: aᵢ · bⱼ = 2π δᵢⱼ
    let p = LatticeParameters::cubic(4.0);
    let rv = p.reciprocal_vectors();
    let lv = p.lattice_vectors();
    let dot = |u: [f64; 3], v: [f64; 3]| u[0] * v[0] + u[1] * v[1] + u[2] * v[2];
    assert!((dot(rv[0], lv[0]) - 2.0 * std::f64::consts::PI).abs() < 1e-8);
    assert!(dot(rv[0], lv[1]).abs() < 1e-8);
    assert!(dot(rv[1], lv[0]).abs() < 1e-8);
}

// ── Point groups → space groups consistency ────────────────────────

#[test]
fn cubic_point_groups_all_centred() {
    // Not all cubic PGs are centrosymmetric (23, 432, -43m are not)
    let cubic: Vec<PointGroup> = PointGroup::all_32()
        .into_iter()
        .filter(|g| g.crystal_system == CrystalSystem::Cubic)
        .collect();
    assert_eq!(cubic.len(), 5, "5 cubic point groups");
    let centrosym = cubic.iter().filter(|g| g.centrosymmetric).count();
    assert_eq!(
        centrosym, 2,
        "2 centrosymmetric cubic groups (m-3 and m-3m)"
    );
}

#[test]
fn symop_group_closure() {
    // C4 × C4 = C2, C2 × C2 = E, C4^4 = E
    let c4 = SymOp::c4z();
    let c4_2 = c4.compose(&c4); // C4² = C2
    let c4_4 = c4_2.compose(&c4_2); // C4⁴ = E
    assert_eq!(c4_4.rot, SymOp::identity().rot, "C4⁴ = E");
}

#[test]
fn space_group_numbers_cover_all_230() {
    assert!(SpaceGroup::is_valid_number(1));
    assert!(SpaceGroup::is_valid_number(115));
    assert!(SpaceGroup::is_valid_number(230));
    assert!(!SpaceGroup::is_valid_number(231));
}

// ── Structure factor pipeline ──────────────────────────────────────

#[test]
fn silicon_f0_near_14() {
    // Si scattering factor at s=0 should be ≈ Z = 14
    let sf = ScatteringFactor::silicon();
    let f0 = sf.eval(0.0);
    assert!((f0 - 14.0).abs() < 0.5, "Si f(0) ≈ 14, got {f0:.2}");
}

#[test]
fn structure_factor_iron_bcc_110() {
    // BCC: (110) is present (h+k+l = 2 = even)
    let fe = CrystalStructure::bcc_iron();
    let m110 = Miller::new(1, 1, 0);
    let d = m110.d_spacing_cubic(fe.lattice.a);
    let mut sf_map = HashMap::new();
    sf_map.insert(
        "Fe".to_owned(),
        ScatteringFactor {
            a: [11.77, 7.068, 3.982, 2.417],
            b: [4.761, 0.307, 15.35, 76.88],
            c: 1.036,
        },
    );
    let (re, im) = structure_factor(&m110, &fe.sites, &sf_map, d, 1.5406);
    let intensity = re * re + im * im;
    assert!(
        intensity > 1.0,
        "Fe BCC (110) should be present, |F|²={intensity:.1}"
    );
}

// ── Bonding pipeline ──────────────────────────────────────────────

#[test]
fn lj_argon_well_depth() {
    let lj = LennardJones::argon();
    // At r_min: V = -ε = -0.0104 eV
    let v = lj.potential(lj.r_min());
    assert!((v - lj.v_min()).abs() < 1e-12);
    assert!(
        (v + 0.0104).abs() < 1e-12,
        "V(r_min) = -0.0104 eV for Ar, got {v}"
    );
}

#[test]
fn madelung_nacl_born_lande_energy() {
    // NaCl Born-Landé: ~-787 kJ/mol
    let u = MadelungStructure::NaCl.lattice_energy_kj_mol(1.0, 1.0, 2.82, 9.0);
    assert!(
        u < -700.0 && u > -900.0,
        "NaCl lattice energy should be -700 to -900 kJ/mol, got {u:.1}"
    );
}

#[test]
fn bvs_silicon_four_coord() {
    // Si⁴⁺ in tetrahedral coordination: 4 bonds each contributing BVS = 1
    // BVS = n_bonds * exp((R0 - R)/b); target = 4
    // For 4 equal bonds: each s = 1, so R = R0 = 1.624 Å
    let bv = BondValence::new();
    let r0 = 1.624_f64; // Si-O R0
    let lengths = vec![r0; 4]; // each bond at R0 gives s=1 per bond
    let sum = bv.bvs("Si", "O", &lengths).unwrap();
    assert!((sum - 4.0).abs() < 0.01, "BVS(Si,4×O@R0) = 4, got {sum:.4}");
}

#[test]
fn pauling_ionicity_naf_vs_hf() {
    // NaF more ionic than HF
    let en_na = pauling_electronegativity("Na").unwrap();
    let en_f = pauling_electronegativity("F").unwrap();
    let en_h = pauling_electronegativity("H").unwrap();
    let ion_naf = pauling_ionicity(en_na, en_f);
    let ion_hf = pauling_ionicity(en_h, en_f);
    assert!(
        ion_naf > ion_hf,
        "NaF more ionic than HF: {ion_naf:.2} > {ion_hf:.2}"
    );
}

// ── Miller indices cross-check ────────────────────────────────────

#[test]
fn miller_zone_law_systematic() {
    // [100] zone axis: planes (0kl) only — h=0
    for k in -2..=2i32 {
        for l in -2..=2i32 {
            let m = Miller::new(0, k, l);
            assert!(m.in_zone(1, 0, 0), "(0{k}{l}) should be in [100] zone");
        }
    }
    // (100) itself is NOT in its own zone axis [100]
    let m100 = Miller::new(1, 0, 0);
    assert!(!m100.in_zone(1, 0, 0), "(100) is not in [100] zone");
}