import assert from "node:assert/strict";
import { describe, it } from "node:test";
import * as ss from "../index.js";

describe("combinations", function () {
    it("generates 1 permutation", function () {
        assert.deepEqual(ss.combinationsReplacement(Object.freeze([1]), 1), [
            [1]
        ]);
    });
    it("generates combinations of 1,2 choosing two at a time, with replacement", function () {
        assert.deepEqual(ss.combinationsReplacement(Object.freeze([1, 2]), 2), [
            [1, 1],
            [1, 2],
            [2, 2]
        ]);
    });
    it("returns no combinations when choosing zero at a time", function () {
        assert.deepEqual(
            ss.combinationsReplacement(Object.freeze([1, 2, 3]), 0),
            []
        );
    });
    it("returns no combinations for a negative group size", function () {
        assert.deepEqual(
            ss.combinationsReplacement(Object.freeze([1, 2, 3]), -1),
            []
        );
    });
    it("agrees with combinations on non-positive group sizes", function () {
        const x = Object.freeze([1, 2, 3]);
        assert.deepEqual(
            ss.combinationsReplacement(x, 0),
            ss.combinations(x, 0)
        );
        assert.deepEqual(
            ss.combinationsReplacement(x, -1),
            ss.combinations(x, -1)
        );
    });
});