//! Tests for the RNG functionality.

use claims::*;
use expy::{Context, Error, EvalError, eval, eval_in};

const TRIES: usize = 256;


#[test]
fn rand_no_args() {
    for _ in 0..TRIES {
        let x = eval("rand()").unwrap().unwrap_float();
        assert_ge!(x, 0.);
        assert_lt!(x, 1.);
    }
}

#[test]
fn rand_one_arg_integer() {
    let mut ctx = Context::new();

    // rand(x) draws from 0..x, so rand(0) doesn't make sense (it'd be an empty range).
    assert_eq!(
        eval("rand(0)").unwrap_err(), Error::Eval(EvalError::argument("positive bound", 0)));

    for _ in 0..TRIES {
        let max = fastrand::i64(1..65536);
        ctx.set("max", max);

        let x = eval_in(&mut ctx, "rand(max)").unwrap().unwrap_integer();
        assert_ge!(x, 0);
        assert_lt!(x, max);
    }
}

#[test]
fn rand_one_arg_float() {
    let mut ctx = Context::new();

    for _ in 0..TRIES {
        let max = fastrand::f32() * 65536.;
        ctx.set("max", max);

        let x = eval_in(&mut ctx, "rand(max)").unwrap().unwrap_float();
        assert_ge!(x, 0.);
        assert_lt!(x, max);
    }
}

#[test]
fn rand_two_args_integers() {
    let mut ctx = Context::new();

    for _ in 0..TRIES {
        let min = fastrand::i64(0..65535);
        let max = fastrand::i64(min..65536);
        ctx.set("min", min);
        ctx.set("max", max);

        let x = eval_in(&mut ctx, "rand(min, max)").unwrap().unwrap_integer();
        assert_ge!(x, min);
        assert_le!(x, max);
    }
}

#[test]
fn rand_two_args_floats() {
    let mut ctx = Context::new();

    for _ in 0..TRIES {
        let min = fastrand::f32() * 65535.;
        let max = min + fastrand::f32() * (65536. - min);
        ctx.set("min", min);
        ctx.set("max", max);

        let x = eval_in(&mut ctx, "rand(min, max)").unwrap().unwrap_float();
        assert_ge!(x, min);
        assert_lt!(x, max);
    }
}