import {QQ} from './QQ'

describe("QQ", function() {
    describe("constructor", function() {
        it("numer matches construction argument", function() {
            const x = QQ.valueOf(3, 5);
            expect(x.numer).toBe(3);
        });
        it("denom matches construction argument", function() {
            const x = QQ.valueOf(3, 5);
            expect(x.denom).toBe(5);
        });
        it("Construction", function() {
            const x = QQ.valueOf(1, 1);
            expect(x.numer).toBe(1);
            expect(x.denom).toBe(1);
        });
        it("Construction on zero", function() {
            const x = QQ.valueOf(0, 1);
            expect(x.numer).toBe(0);
            expect(x.denom).toBe(1);
        });
        it("GCD", function() {
            const x = QQ.valueOf(2, 2);
            expect(x.numer).toBe(1);
            expect(x.denom).toBe(1);
        });
        it("Canonical (-1,3) => (-1,3)", function() {
            const x = QQ.valueOf(-1, 3);
            expect(x.numer).toBe(-1);
            expect(x.denom).toBe(3);
        });
        it("Canonical (1,-3) => (-1,3)", function() {
            const x = QQ.valueOf(1, -3);
            expect(x.numer).toBe(-1);
            expect(x.denom).toBe(3);
        });
        it("add QQ", function() {
            const x = QQ.valueOf(1, 3);
            const y = QQ.valueOf(2, 1);
            const sum = x.add(y);
            expect(sum.numer).toBe(7);
            expect(sum.denom).toBe(3);
            expect(x.numer).toBe(1);
            expect(x.denom).toBe(3);
            expect(y.numer).toBe(2);
            expect(y.denom).toBe(1);
        });
        it("sub QQ", function() {
            const x = QQ.valueOf(1, 3);
            const y = QQ.valueOf(2, 1);
            const sum = x.sub(y);
            expect(sum.numer).toBe(-5);
            expect(sum.denom).toBe(3);
            expect(x.numer).toBe(1);
            expect(x.denom).toBe(3);
            expect(y.numer).toBe(2);
            expect(y.denom).toBe(1);
        });
        it("mul", function() {
            const x = QQ.valueOf(1, 3);
            const y = QQ.valueOf(2, 1);
            const sum = x.mul(y);
            expect(sum.numer).toBe(2);
            expect(sum.denom).toBe(3);
            expect(x.numer).toBe(1);
            expect(x.denom).toBe(3);
            expect(y.numer).toBe(2);
            expect(y.denom).toBe(1);
        });
        it("div", function() {
            const x = QQ.valueOf(0, 1);
            const y = QQ.valueOf(2, 1);
            const q = x.div(y);
            expect(q.numer).toBe(0);
            expect(q.denom).toBe(1);
            expect(x.numer).toBe(0);
            expect(x.denom).toBe(1);
            expect(y.numer).toBe(2);
            expect(y.denom).toBe(1);
        });
        it("neg() should change the sign of the numerator", function() {
            const x = QQ.valueOf(1, 3);
            const n = x.neg();
            expect(x.numer).toBe(+1);
            expect(n.numer).toBe(-1);
        });
        it("neg() should leave the denominator unchanged", function() {
            const x = QQ.valueOf(1, 3);
            const n = x.neg();
            expect(x.denom).toBe(+3);
            expect(n.denom).toBe(+3);
        });
        it("toString", function() {
            const x = QQ.valueOf(1, 2);
            expect("" + x).toBe("1/2");
        });
        describe("valueOf", function() {
            it("should return an equivalent number", function() {
                for (let n = -10; n < 10; n++) {
                    for (let d = -10; d < 10; d++) {
                        if (d !== 0) {
                            const x = QQ.valueOf(n, d)
                            expect(x.numer * d).toBe(x.denom * n)
                            if (n === 0) {
                                expect(x).toEqual(QQ.valueOf(0, 1))
                            }
                            else if (n === +d) {
                                expect(x).toEqual(QQ.valueOf(+1, 1))
                            }
                            else if (n === -d) {
                                expect(x).toEqual(QQ.valueOf(-1, 1))
                            }
                        }
                    }
                }
            })
        });
    });
});