circomlib/test/binsub.js

const chai = require("chai");
const path = require("path");
const snarkjs = require("@tornado/snarkjs");
const compiler = require("circom");

const assert = chai.assert;

const bigInt = snarkjs.bigInt;

function print(circuit, w, s) {
    console.log(s + ": " + w[circuit.getSignalIdx(s)]);
}

function checkSub(_a, _b, circuit) {
    let a = bigInt(_a);
    let b = bigInt(_b);
    if (a.lesser(bigInt.zero)) a = a.add(bigInt.one.shl(16));
    if (b.lesser(bigInt.zero)) b = b.add(bigInt.one.shl(16));
    const w = circuit.calculateWitness({ a: a, b: b });

    let res = a.sub(b);
    if (res.lesser(bigInt.zero)) res = res.add(bigInt.one.shl(16));
    assert(w[circuit.getSignalIdx("main.out")].equals(bigInt(res)));
}

describe("BinSub test", () => {
    let circuit;
    before(async () => {
        const cirDef = await compiler(path.join(__dirname, "circuits", "binsub_test.circom"));

        circuit = new snarkjs.Circuit(cirDef);

        console.log("NConstrains BinSub: " + circuit.nConstraints);
    });

    it("Should check variuos ege cases", async () => {
        checkSub(0, 0, circuit);
        checkSub(1, 0, circuit);
        checkSub(-1, 0, circuit);
        checkSub(2, 1, circuit);
        checkSub(2, 2, circuit);
        checkSub(2, 3, circuit);
        checkSub(2, -1, circuit);
        checkSub(2, -2, circuit);
        checkSub(2, -3, circuit);
        checkSub(-2, -3, circuit);
        checkSub(-2, -2, circuit);
        checkSub(-2, -1, circuit);
        checkSub(-2, 0, circuit);
        checkSub(-2, 1, circuit);
        checkSub(-2, 2, circuit);
        checkSub(-2, 3, circuit);
    });
});