random.mjs

/** nodejs doesnt support window.crypt */
import {expect} from "chai"

describe('Math', function () {

    let random = () => {}
    
    before(function (done) {

        let promises = []
        if (!globalThis['crypto']) {
            promises.push(import("@peculiar/webcrypto").then(m => {
                globalThis['crypto'] = new m.Crypto();
                return true;
            }))
        }

        promises.push(import("../../../source/math/random.mjs").then(m => {
            random = m.random;
            return true;
        }))


        Promise.all(promises).then(() => {
            done()
        });

    });

    describe('.random()', function () {


        it('a greater b should throw error ', function () {
            expect(() => random(10, 2)).to.throw(Error);
        });

        it(' should return a number ', function () {
            let r = random();
            expect(r).that.is.a('number');
        });

        it(' should return a number ', function () {
            expect(() => random(5, 6)).to.throw(Error);
        });

        it(' should throw Error we cannot generate numbers larger than 53 bits.', function () {
            expect(() => random(-999999999, 99999999999999999999)).to.throw(Error);
        });

        it(' should throw Error we cannot generate numbers larger than 53 bits.', function () {

            [
                [1, 100],
                [500, 600],
                [100, 1000]
            ].forEach(function (data) {

                let a = data.shift()
                let b = data.shift()

                let r = random(a, b);

                it(r + ' should return value between ' + a + ' ' + b, function () {
                    expect(r >= a).to.be.true;
                    expect(r <= b).to.be.true;
                });
            });

            [
                [1, 100],
                [500, 600],
                [100, 1000]
            ].forEach(function (data) {

                let a = data.shift()
                let b = data.shift()

                let sum = 0;
                const rounds = 500

                for (let i = 0, max = rounds; i < max; i++) {
                    sum += random(a, b);
                }

                let avg = sum / rounds;

                it(avg + ' should between ' + a + ' ' + b, function () {
                    expect(avg > a).to.be.true
                    expect(avg < b).to.be.true
                })


            })

        })


    })


})