mpzjs/test/mul.test.js

Arbitrary-precision integer arithmetic using libgmp

const MPZ = require('../');

test('mul', () => {
    [-100, -10, -5, -1, 0, 1, 5, 10, 100].forEach(i => {
        [-100, -10, -5, -1, 0, 1, 5, 10, 100].forEach(j => {
            const js = j.toString();
            const ks = (i * j).toString();
            const result = MPZ();

            expect(MPZ(i).mul(j).toString()).toBe(ks);
            expect(MPZ(i).mul(js).toString()).toBe(ks);
            expect(MPZ(i).mul(MPZ(j)).toString()).toBe(ks);
            expect(MPZ(i).mul(BigInt(j)).toString()).toBe(ks);

            MPZ.mul(result, i, j);
            expect(result.toString()).toBe(ks);
            MPZ.mul(result, i, js);
            expect(result.toString()).toBe(ks);
            MPZ.mul(result, MPZ(i), MPZ(j));
            expect(result.toString()).toBe(ks);
        });
    });

    expect(
        MPZ(
            '433593290010590489671135819286259593426549306666324008679782084292'
            + '2446494189019075159822930571858728009485237489829138626896756141'
            + '8738958337632249177044975686477011571044266'
        ).mul(
            '127790264841901718791915669264129510947625523373763053776083279450'
            + '3886212911067061184379695097643279217271150419129022856601771338'
            + '794256383410400076210073482253089544155377'
        ).toString()
    ).toBe(
        '5540900136412485758752141142221047463857522755277604708501015732755989'
        + '17659432099233635577634197309727815375309484297883528869192732141328'
        + '99346769031695550850320602049507618052164677667378189154076988316301'
        + '23719953859959804490669091769150047414629675184805332001182298088891'
        + '58079529848220802017396422115936618644438110463469902675126288489182'
        + '82'
    );

    expect(MPZ('10000000000000000000000000000').mul(-123).toString())
        .toBe('-1230000000000000000000000000000');
});

test('mul exceptions', () => {
    expect(() => {
        MPZ.mul(1, 2);
    }).toThrow();

    expect(() => {
        MPZ.mul(MPZ(1), MPZ(2));
    }).toThrow();

    expect(() => {
        MPZ.mul(MPZ(1));
    }).toThrow();
});