Cagire/tests/forth/randomness.rs

use super::harness::*;

#[test]
fn rand_in_range() {
    let f = forth_seeded(12345);
    f.evaluate("0 10 rand", &default_ctx()).unwrap();
    let val = stack_float(&f);
    assert!(val >= 0.0 && val < 10.0, "rand {} not in [0, 10)", val);
}

#[test]
fn rand_deterministic() {
    let f1 = forth_seeded(99);
    let f2 = forth_seeded(99);
    f1.evaluate("0 100 rand", &default_ctx()).unwrap();
    f2.evaluate("0 100 rand", &default_ctx()).unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn seed_resets() {
    let f1 = forth_seeded(1);
    f1.evaluate("42 seed 0 100 rand", &default_ctx()).unwrap();
    let f2 = forth_seeded(999);
    f2.evaluate("42 seed 0 100 rand", &default_ctx()).unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn coin_binary() {
    let f = forth_seeded(42);
    f.evaluate("coin", &default_ctx()).unwrap();
    let val = stack_int(&f);
    assert!(val == 0 || val == 1);
}

#[test]
fn chance_zero() {
    // 0.0 probability should never execute the quotation
    let f = run("99 { 42 } 0.0 chance");
    assert_eq!(stack_int(&f), 99); // quotation not executed, 99 still on stack
}

#[test]
fn chance_one() {
    // 1.0 probability should always execute the quotation
    let f = run("{ 42 } 1.0 chance");
    assert_eq!(stack_int(&f), 42);
}

#[test]
fn choose_from_list() {
    let f = forth_seeded(42);
    f.evaluate("10 20 30 3 choose", &default_ctx()).unwrap();
    let val = stack_int(&f);
    assert!(val == 10 || val == 20 || val == 30);
}

#[test]
fn choose_underflow() {
    expect_error("1 2 5 choose", "stack underflow");
}

#[test]
fn cycle_deterministic() {
    for runs in 0..6 {
        let ctx = ctx_with(|c| c.runs = runs);
        let f = run_ctx("10 20 30 3 cycle", &ctx);
        let expected = [10, 20, 30][runs % 3];
        assert_eq!(stack_int(&f), expected, "cycle at runs={}", runs);
    }
}

#[test]
fn cycle_zero_count() {
    expect_error("1 2 3 0 cycle", "cycle count must be > 0");
}

#[test]
fn mtof_a4() {
    expect_float("69 mtof", 440.0);
}

#[test]
fn mtof_octave() {
    expect_float("81 mtof", 880.0);
}

#[test]
fn mtof_c4() {
    expect_floats_close("60 mtof", 261.6255653, 0.001);
}

#[test]
fn ftom_440() {
    expect_float("440 ftom", 69.0);
}

#[test]
fn ftom_880() {
    expect_float("880 ftom", 81.0);
}

#[test]
fn mtof_ftom_roundtrip() {
    expect_float("60 mtof ftom", 60.0);
}

#[test]
fn exprand_in_range() {
    let f = forth_seeded(12345);
    f.evaluate("1.0 100.0 exprand", &default_ctx()).unwrap();
    let val = stack_float(&f);
    assert!(val >= 1.0 && val <= 100.0, "exprand {} not in [1, 100]", val);
}

#[test]
fn exprand_deterministic() {
    let f1 = forth_seeded(99);
    let f2 = forth_seeded(99);
    f1.evaluate("1.0 100.0 exprand", &default_ctx()).unwrap();
    f2.evaluate("1.0 100.0 exprand", &default_ctx()).unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn exprand_swapped_args() {
    let f1 = forth_seeded(42);
    let f2 = forth_seeded(42);
    f1.evaluate("1.0 100.0 exprand", &default_ctx()).unwrap();
    f2.evaluate("100.0 1.0 exprand", &default_ctx()).unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn exprand_requires_positive() {
    expect_error("0.0 10.0 exprand", "exprand requires positive values");
    expect_error("-1.0 10.0 exprand", "exprand requires positive values");
    expect_error("1.0 0.0 exprand", "exprand requires positive values");
}

#[test]
fn logrand_in_range() {
    let f = forth_seeded(12345);
    f.evaluate("1.0 100.0 logrand", &default_ctx()).unwrap();
    let val = stack_float(&f);
    assert!(val >= 1.0 && val <= 100.0, "logrand {} not in [1, 100]", val);
}

#[test]
fn logrand_deterministic() {
    let f1 = forth_seeded(99);
    let f2 = forth_seeded(99);
    f1.evaluate("1.0 100.0 logrand", &default_ctx()).unwrap();
    f2.evaluate("1.0 100.0 logrand", &default_ctx()).unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn logrand_swapped_args() {
    let f1 = forth_seeded(42);
    let f2 = forth_seeded(42);
    f1.evaluate("1.0 100.0 logrand", &default_ctx()).unwrap();
    f2.evaluate("100.0 1.0 logrand", &default_ctx()).unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn logrand_requires_positive() {
    expect_error("0.0 10.0 logrand", "logrand requires positive values");
    expect_error("-1.0 10.0 logrand", "logrand requires positive values");
    expect_error("1.0 0.0 logrand", "logrand requires positive values");
}

#[test]
fn rand_equal_bounds() {
    expect_float("5.0 5.0 rand", 5.0);
}

// bounce

#[test]
fn bounce_sequence() {
    let expected = [60, 64, 67, 72, 67, 64, 60, 64];
    for (runs, &exp) in expected.iter().enumerate() {
        let ctx = ctx_with(|c| c.runs = runs);
        let f = run_ctx("60 64 67 72 4 bounce", &ctx);
        assert_eq!(stack_int(&f), exp, "bounce at runs={}", runs);
    }
}

#[test]
fn bounce_single() {
    for runs in 0..5 {
        let ctx = ctx_with(|c| c.runs = runs);
        let f = run_ctx("42 1 bounce", &ctx);
        assert_eq!(stack_int(&f), 42, "bounce single at runs={}", runs);
    }
}

#[test]
fn bounce_zero_count() {
    expect_error("1 2 3 0 bounce", "bounce count must be > 0");
}

#[test]
fn bounce_underflow() {
    expect_error("1 2 5 bounce", "stack underflow");
}

// wchoose

#[test]
fn wchoose_all_weight_one_item() {
    for _ in 0..10 {
        let f = forth_seeded(42);
        f.evaluate("10 0.0  20 1.0  2 wchoose", &default_ctx())
            .unwrap();
        assert_eq!(stack_int(&f), 20);
    }
}

#[test]
fn wchoose_deterministic() {
    let f1 = forth_seeded(99);
    let f2 = forth_seeded(99);
    f1.evaluate("60 0.6  64 0.3  67 0.1  3 wchoose", &default_ctx())
        .unwrap();
    f2.evaluate("60 0.6  64 0.3  67 0.1  3 wchoose", &default_ctx())
        .unwrap();
    assert_eq!(f1.stack(), f2.stack());
}

#[test]
fn wchoose_zero_count() {
    expect_error("0 wchoose", "wchoose count must be > 0");
}

#[test]
fn wchoose_underflow() {
    expect_error("10 0.5 2 wchoose", "stack underflow");
}

#[test]
fn wchoose_negative_weight() {
    expect_error("10 -0.5  20 1.0  2 wchoose", "negative weight");
}

#[test]
fn wchoose_quotation() {
    let f = forth_seeded(42);
    f.evaluate("{ 10 } 0.0  { 20 } 1.0  2 wchoose", &default_ctx())
        .unwrap();
    assert_eq!(stack_int(&f), 20);
}