aprender-core 0.29.1

pub(crate) use super::*;

#[test]
fn test_from_slice() {
    let v = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    assert_eq!(v.len(), 3);
    assert!((v[0] - 1.0).abs() < 1e-6);
}

#[test]
fn test_zeros() {
    let v = Vector::<f32>::zeros(5);
    assert_eq!(v.len(), 5);
    assert!(v.as_slice().iter().all(|&x| x == 0.0));
}

#[test]
fn test_ones() {
    let v = Vector::<f32>::ones(5);
    assert_eq!(v.len(), 5);
    assert!(v.as_slice().iter().all(|&x| (x - 1.0).abs() < 1e-6));
}

#[test]
fn test_sum() {
    let v = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    assert!((v.sum() - 6.0).abs() < 1e-6);
}

#[test]
fn test_mean() {
    let v = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    assert!((v.mean() - 2.0).abs() < 1e-6);
}

#[test]
fn test_dot() {
    let a = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    let b = Vector::from_slice(&[4.0_f32, 5.0, 6.0]);
    assert!((a.dot(&b) - 32.0).abs() < 1e-6);
}

#[test]
fn test_add_scalar() {
    let v = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    let result = v.add_scalar(10.0);
    assert!((result[0] - 11.0).abs() < 1e-6);
    assert!((result[1] - 12.0).abs() < 1e-6);
    assert!((result[2] - 13.0).abs() < 1e-6);
}

#[test]
fn test_mul_scalar() {
    let v = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    let result = v.mul_scalar(2.0);
    assert!((result[0] - 2.0).abs() < 1e-6);
    assert!((result[1] - 4.0).abs() < 1e-6);
    assert!((result[2] - 6.0).abs() < 1e-6);
}

#[test]
fn test_norm() {
    let v = Vector::from_slice(&[3.0_f32, 4.0]);
    assert!((v.norm() - 5.0).abs() < 1e-6);
}

#[test]
fn test_argmin() {
    let v = Vector::from_slice(&[3.0_f32, 1.0, 2.0]);
    assert_eq!(v.argmin(), 1);
}

#[test]
fn test_argmax() {
    let v = Vector::from_slice(&[3.0_f32, 1.0, 2.0]);
    assert_eq!(v.argmax(), 0);
}

#[test]
fn test_variance() {
    let v = Vector::from_slice(&[2.0_f32, 4.0, 4.0, 4.0, 5.0, 5.0, 7.0, 9.0]);
    assert!((v.variance() - 4.0).abs() < 1e-6);
}

#[test]
fn test_add_vectors() {
    let a = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    let b = Vector::from_slice(&[4.0_f32, 5.0, 6.0]);
    let result = &a + &b;
    assert!((result[0] - 5.0).abs() < 1e-6);
    assert!((result[1] - 7.0).abs() < 1e-6);
    assert!((result[2] - 9.0).abs() < 1e-6);
}

#[test]
fn test_sub_vectors() {
    let a = Vector::from_slice(&[4.0_f32, 5.0, 6.0]);
    let b = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    let result = &a - &b;
    assert!((result[0] - 3.0).abs() < 1e-6);
    assert!((result[1] - 3.0).abs() < 1e-6);
    assert!((result[2] - 3.0).abs() < 1e-6);
}

#[test]
fn test_slice() {
    let v = Vector::from_slice(&[1.0_f32, 2.0, 3.0, 4.0, 5.0]);
    let sliced = v.slice(1, 4);
    assert_eq!(sliced.len(), 3);
    assert!((sliced[0] - 2.0).abs() < 1e-6);
    assert!((sliced[2] - 4.0).abs() < 1e-6);
}

#[test]
fn test_empty_mean() {
    let v = Vector::<f32>::from_vec(vec![]);
    assert!((v.mean() - 0.0).abs() < 1e-6);
}

#[test]
fn test_is_empty() {
    let empty = Vector::<f32>::from_vec(vec![]);
    assert!(empty.is_empty());

    let non_empty = Vector::from_slice(&[1.0_f32]);
    assert!(!non_empty.is_empty());
}

#[test]
fn test_argmax_single_element() {
    let v = Vector::from_slice(&[42.0_f32]);
    assert_eq!(v.argmax(), 0);
}

#[test]
fn test_argmax_all_equal() {
    let v = Vector::from_slice(&[5.0_f32, 5.0, 5.0]);
    let idx = v.argmax();
    // When all equal, any valid index is acceptable
    assert!(idx < v.len());
    assert!((v[idx] - 5.0).abs() < 1e-6);
}

#[test]
fn test_argmin_single_element() {
    let v = Vector::from_slice(&[42.0_f32]);
    assert_eq!(v.argmin(), 0);
}

#[test]
fn test_argmin_all_equal() {
    let v = Vector::from_slice(&[5.0_f32, 5.0, 5.0]);
    let idx = v.argmin();
    // When all equal, any valid index is acceptable
    assert!(idx < v.len());
    assert!((v[idx] - 5.0).abs() < 1e-6);
}

#[test]
fn test_argmax_not_at_zero() {
    // Max at index 2, not 0 - catches "argmax -> 0" mutation
    let v = Vector::from_slice(&[1.0_f32, 2.0, 10.0]);
    assert_eq!(v.argmax(), 2);
}

#[test]
fn test_mul_vectors() {
    // Element-wise multiplication - catches operator mutations
    let a = Vector::from_slice(&[2.0_f32, 3.0, 4.0]);
    let b = Vector::from_slice(&[5.0_f32, 6.0, 7.0]);
    let result = &a * &b;
    // 2*5=10, 3*6=18, 4*7=28
    assert!((result[0] - 10.0).abs() < 1e-6);
    assert!((result[1] - 18.0).abs() < 1e-6);
    assert!((result[2] - 28.0).abs() < 1e-6);

    // Verify it's not addition: would be 7, 9, 11
    assert!((result[0] - 7.0).abs() > 0.1);
    // Verify it's not division: would be 0.4, 0.5, 0.571...
    assert!((result[1] - 0.5).abs() > 1.0);
}

#[test]
fn test_is_empty_true() {
    // Test that empty vector returns true for is_empty
    // Catches is_empty -> false mutation
    let v: Vector<f32> = Vector::from_slice(&[]);
    assert!(v.is_empty(), "Empty vector should return true for is_empty");
    assert_eq!(v.len(), 0, "Empty vector should have len 0");
}

#[test]
fn test_is_empty_false() {
    // Test that non-empty vector returns false for is_empty
    let v = Vector::from_slice(&[1.0_f32]);
    assert!(
        !v.is_empty(),
        "Non-empty vector should return false for is_empty"
    );
}

#[test]
fn test_argmin_not_at_one() {
    // Min at index 0, not 1 - catches "argmin -> 1" mutation
    let v = Vector::from_slice(&[1.0_f32, 5.0, 3.0]);
    assert_eq!(v.argmin(), 0, "Minimum should be at index 0, not 1");
}

#[test]
fn test_argmin_at_end() {
    // Min at last index - catches various index mutations
    let v = Vector::from_slice(&[5.0_f32, 3.0, 1.0]);
    assert_eq!(v.argmin(), 2, "Minimum should be at index 2");
}

#[test]
fn test_as_mut_slice_modifies() {
    // Test that as_mut_slice actually allows modification
    // Catches as_mut_slice -> empty slice mutation
    let mut v = Vector::from_slice(&[1.0_f32, 2.0, 3.0]);
    {
        let slice = v.as_mut_slice();
        slice[0] = 10.0;
        slice[1] = 20.0;
    }
    assert!(
        (v[0] - 10.0).abs() < 1e-6,
        "First element should be modified to 10.0"
    );
    assert!(
        (v[1] - 20.0).abs() < 1e-6,
        "Second element should be modified to 20.0"
    );
}

#[test]
fn test_as_mut_slice_length() {
    // Verify as_mut_slice returns correct length
    let mut v = Vector::from_slice(&[1.0_f32, 2.0, 3.0, 4.0]);
    let slice = v.as_mut_slice();
    assert_eq!(slice.len(), 4, "Mutable slice should have correct length");
}

// EXTREME TDD: Additional mutation-killing tests
// These tests explicitly target MISSED mutants reported by cargo-mutants

#[test]
fn test_argmax_f32_returns_nonzero() {
    // MUTATION TARGET: "replace Vector<f32>::argmax -> usize with 0"
    // This test ensures argmax() does NOT always return 0
    let v: Vector<f32> = Vector::from_slice(&[1.0, 2.0, 999.0, 3.0]);
    assert_eq!(
        v.argmax(),
        2,
        "argmax must return 2 (position of max 999.0), not 0"
    );
    // Double check: if mutation makes argmax() return 0, this fails
    assert_ne!(v.argmax(), 0, "argmax must not always return 0");
}

#[test]
fn test_as_mut_slice_f32_not_empty() {
    // MUTATION TARGET: "replace as_mut_slice -> &mut[T] with Vec::leak(Vec::new())"
    // This test ensures as_mut_slice() does NOT return empty slice
    let mut v: Vector<f32> = Vector::from_slice(&[10.0, 20.0, 30.0]);
    let slice = v.as_mut_slice();

    // If mutation returns empty slice, len check fails
    assert_eq!(
        slice.len(),
        3,
        "as_mut_slice must return slice with 3 elements, not empty"
    );

    // If mutation returns empty slice, modification has no effect
    slice[0] = 100.0;
    assert!(
        (v[0] - 100.0).abs() < 1e-6,
        "as_mut_slice must allow mutation of original data"
    );
}

#[test]
fn test_mul_f32_not_addition() {
    // MUTATION TARGET: "replace * with + in <impl Mul for &Vector<f32>>::mul"
    // This test ensures Mul uses *, not +
    let a: Vector<f32> = Vector::from_slice(&[3.0, 4.0]);
    let b: Vector<f32> = Vector::from_slice(&[5.0, 6.0]);
    let result = &a * &b;

    // Multiplication: [3*5=15, 4*6=24]
    assert!(
        (result[0] - 15.0).abs() < 1e-6,
        "3*5 must equal 15, not 3+5=8"
    );
    assert!(
        (result[1] - 24.0).abs() < 1e-6,
        "4*6 must equal 24, not 4+6=10"
    );

    // If mutation uses +, we get [8, 10] instead
    assert!((result[0] - 8.0).abs() > 1.0, "Must not be addition");
    assert!((result[1] - 10.0).abs() > 1.0, "Must not be addition");
}

#[test]
fn test_mul_f32_not_division() {
    // MUTATION TARGET: "replace * with / in <impl Mul for &Vector<f32>>::mul"
    // This test ensures Mul uses *, not /
    let a: Vector<f32> = Vector::from_slice(&[12.0, 20.0]);
    let b: Vector<f32> = Vector::from_slice(&[3.0, 4.0]);
    let result = &a * &b;

    // Multiplication: [12*3=36, 20*4=80]
    assert!(
        (result[0] - 36.0).abs() < 1e-6,
        "12*3 must equal 36, not 12/3=4"
    );
    assert!(
        (result[1] - 80.0).abs() < 1e-6,
        "20*4 must equal 80, not 20/4=5"
    );

    // If mutation uses /, we get [4, 5] instead
    assert!((result[0] - 4.0).abs() > 1.0, "Must not be division");
    assert!((result[1] - 5.0).abs() > 1.0, "Must not be division");
}

#[test]
fn test_std() {
    // Test standard deviation calculation
    let v = Vector::from_slice(&[1.0, 2.0, 3.0, 4.0, 5.0]);
    let std = v.std();

    // Expected: sqrt(variance) = sqrt(2.0) ≈ 1.414
    assert!((std - 1.414).abs() < 0.01, "std = {std}");
}

#[test]
fn test_std_uniform() {
    // Uniform values should have std = 0
    let v = Vector::from_slice(&[5.0, 5.0, 5.0, 5.0]);
    assert!((v.std() - 0.0).abs() < 1e-6);
}

#[test]
fn test_gini_coefficient_perfect_equality() {
    // All values equal -> Gini = 0
    let v = Vector::from_slice(&[5.0, 5.0, 5.0, 5.0]);
    assert!((v.gini_coefficient() - 0.0).abs() < 0.01);
}

#[test]
fn test_gini_coefficient_inequality() {
    // Some inequality
    let v = Vector::from_slice(&[1.0, 2.0, 3.0, 4.0, 5.0]);
    let gini = v.gini_coefficient();

    // Should be between 0 and 1
    assert!(gini > 0.0 && gini < 1.0, "Gini = {gini}");

    // For this specific distribution: Gini ≈ 0.267
    assert!((gini - 0.267).abs() < 0.01, "Gini = {gini}");
}

#[test]
fn test_gini_coefficient_maximum_inequality() {
    // Maximum inequality: one person has everything
    let v = Vector::from_slice(&[0.0, 0.0, 0.0, 100.0]);
    let gini = v.gini_coefficient();

    // Should approach 1.0 (but exact value depends on n)
    // For n=4: Gini = 0.75
    assert!(gini > 0.7 && gini < 0.8, "Gini = {gini}");
}

#[test]
fn test_gini_coefficient_empty() {
    let v: Vector<f32> = Vector::from_slice(&[]);
    assert_eq!(v.gini_coefficient(), 0.0);
}