2d-point/test.js

2D point object

var Point;

beforeEach(function () {
    Point = require('./index.js');
});

describe('Point', function () {
    describe('initialisation', function () {
        it('from two coordinates', function () {
            var pt = Point.create(2, 3);
            expect(pt.x).toEqual(2);
            expect(pt.y).toEqual(3);
        });

        it('should be a point object', function () {
            var pt = Point.create(2, 3);
            expect(Point.isPoint(pt)).toBe(true);
        });

        it('should not validate plain objects', function () {
            expect(Point.isPoint({x: 2, y: 3})).toBe(false);
        });

        it('should default to origin point', function () {
            var pt = Point.create();
            expect(pt.x).toEqual(0);
            expect(pt.y).toEqual(0);
        });

        it('should create a frozen object', function () {
            var pt = Point.create();
            expect(Object.isFrozen(pt)).toBe(true);
        });
    });

    describe('simple geometric operations', function () {
        var p1, p2, p3;
        beforeEach(function () {
            p1 = Point.create(2, 3);
            p2 = Point.create(4, 5);
        });

        it('should be able to add points', function () {
            p3 = Point.add(p1, p2);
            expect(p3.x).toEqual(6);
            expect(p3.y).toEqual(8);
        });

        it('should be able to subtract points', function () {
            p3 = Point.subtract(p1, p2);
            expect(p3.x).toEqual(-2);
            expect(p3.y).toEqual(-2);
        });

        it('should be able to multiply by a scalar', function () {
            p3 = Point.multiply(3, p1);
            expect(p3.x).toEqual(6);
            expect(p3.y).toEqual(9);
        });
    });

    describe('fitting to bounding box', function () {
        var p1, p2;
        beforeEach(function () {
            p1 = Point.create(2, 2);
        });

        it('should fit a landscape point', function () {
            p2 = Point.fitWithin(p1, Point.create(4, 2));
            expect(p2.x).toEqual(2);
            expect(p2.y).toEqual(1);
        });

        it('should fit a portrait point', function () {
            p2 = Point.fitWithin(p1, Point.create(2, 4));
            expect(p2.x).toEqual(1);
            expect(p2.y).toEqual(2);
        });
    });

    describe('fitting to one bounding dimension', function () {
        var p1, p2;
        beforeEach(function () {
            p1 = Point.create(2, 2);
        });

        it('should fit a landscape point', function () {
            p2 = Point.fitOnce(p1, Point.create(8, 4));
            expect(p2.x).toEqual(4);
            expect(p2.y).toEqual(2);
        });

        it('should fit a portrait point', function () {
            p2 = Point.fitOnce(p1, Point.create(4, 8));
            expect(p2.x).toEqual(2);
            expect(p2.y).toEqual(4);
        });
    });
});