lodash/test/random.spec.js

import lodashStable from 'lodash';
import { MAX_INTEGER, stubTrue } from './utils';
import random from '../src/random';

describe('random', () => {
    const array = Array(1000);

    it('should return `0` or `1` when no arguments are given', () => {
        const actual = lodashStable.uniq(lodashStable.map(array, () => random())).sort();

        expect(actual).toEqual([0, 1]);
    });

    it('should support a `min` and `max`', () => {
        const min = 5;
        const max = 10;

        expect(
            lodashStable.some(array, () => {
                const result = random(min, max);
                return result >= min && result <= max;
            }),
        );
    });

    it('should support not providing a `max`', () => {
        const min = 0;
        const max = 5;

        expect(
            lodashStable.some(array, () => {
                const result = random(max);
                return result >= min && result <= max;
            }),
        );
    });

    it('should swap `min` and `max` when `min` > `max`', () => {
        const min = 4;
        const max = 2;
        const expected = [2, 3, 4];

        const actual = lodashStable.uniq(lodashStable.map(array, () => random(min, max))).sort();

        expect(actual).toEqual(expected);
    });

    it('should support large integer values', () => {
        const min = 2 ** 31;
        const max = 2 ** 62;

        expect(
            lodashStable.every(array, () => {
                const result = random(min, max);
                return result >= min && result <= max;
            }),
        );

        expect(lodashStable.some(array, () => random(MAX_INTEGER)))
    });

    it('should coerce arguments to finite numbers', () => {
        const actual = [random(NaN, NaN), random('1', '1'), random(Infinity, Infinity)];

        expect(actual).toEqual([0, 1, MAX_INTEGER]);
    });

    it('should support floats', () => {
        const min = 1.5;
        const max = 1.6;
        const actual = random(min, max);

        expect(actual % 1)
        expect(actual >= min && actual <= max)
    });

    it('should support providing a `floating`', () => {
        let actual = random(true);
        expect(actual % 1 && actual >= 0 && actual <= 1)

        actual = random(2, true);
        expect(actual % 1 && actual >= 0 && actual <= 2)

        actual = random(2, 4, true);
        expect(actual % 1 && actual >= 2 && actual <= 4)
    });

    it('should work as an iteratee for methods like `_.map`', () => {
        const array = [1, 2, 3];
        const expected = lodashStable.map(array, stubTrue);
        const randoms = lodashStable.map(array, random);

        const actual = lodashStable.map(
            randoms,
            (result, index) => result >= 0 && result <= array[index] && result % 1 === 0,
        );

        expect(actual).toEqual(expected);
    });
});