1const path = require("path");
 2const F1Field = require("ffjavascript").F1Field;
 3const Scalar = require("ffjavascript").Scalar;
 4exports.p = Scalar.fromString("21888242871839275222246405745257275088548364400416034343698204186575808495617");
 5const Fr = new F1Field(exports.p);
 6const wasm_tester = require("circom_tester").wasm;
 7
 8function print(circuit, w, s) {
 9    console.log(s + ": " + w[circuit.getSignalIdx(s)]);
10}
11
12function getBits(v, n) {
13    const res = [];
14    for (let i=0; i<n; i++) {
15        if (Scalar.isOdd(Scalar.shr(v, i))) {
16            res.push(Fr.one);
17        } else {
18            res.push(Fr.zero);
19        }
20    }
21    return res;
22}
23
24const q = Scalar.fromString("21888242871839275222246405745257275088548364400416034343698204186575808495617");
25
26describe("Sign test", function() {
27    let circuit;
28    this.timeout(100000);
29
30    before( async() => {
31        circuit = await wasm_tester(path.join(__dirname, "circuits", "sign_test.circom"));
32    });
33
34    it("Sign of 0", async () => {
35        const inp = getBits(Scalar.e(0), 254);
36        const w = await circuit.calculateWitness({in: inp}, true);
37
38        await circuit.assertOut(w, {sign: 0});
39    });
40
41    it("Sign of 3", async () => {
42        const inp = getBits(Scalar.e(3), 254);
43        const w = await circuit.calculateWitness({in: inp}, true);
44
45        await circuit.assertOut(w, {sign: 0});
46    });
47
48    it("Sign of q/2", async () => {
49        const inp = getBits(Scalar.shr(q, 1), 254);
50        const w = await circuit.calculateWitness({in: inp}, true);
51
52        await circuit.assertOut(w, {sign: 0});
53    });
54
55    it("Sign of q/2+1", async () => {
56        const inp = getBits(Scalar.add(Scalar.shr(q, 1), 1) , 254);
57        const w = await circuit.calculateWitness({in: inp}, true);
58
59        await circuit.assertOut(w, {sign: 1});
60    });
61
62    it("Sign of q-1", async () => {
63        const inp = getBits(Scalar.sub(q, 1), 254);
64        const w = await circuit.calculateWitness({in: inp}, true);
65
66        await circuit.assertOut(w, {sign: 1});
67    });
68
69    it("Sign of q", async () => {
70        const inp = getBits(q, 254);
71        const w = await circuit.calculateWitness({in: inp}, true);
72
73        await circuit.assertOut(w, {sign: 1});
74    });
75
76    it("Sign of all ones", async () => {
77        const inp = getBits(Scalar.sub(Scalar.shl(1,254),1), 254);
78        const w = await circuit.calculateWitness({in: inp}, true);
79
80        await circuit.assertOut(w, {sign: 1});
81    });
82});