michaelangelo/test/testArc.js

A lightweight wrapper for RaphaelJS.

/* global describe, it, beforeEach*/
var Arc, assert, sinon;

assert = require('assert');
sinon = require('sinon');
Arc = require('../lib/arc');

describe('arc', function () {
  it('validateAttributes does not throw exception for accepted attributes', function () {
    var arc;
    arc = new Arc({cx: 2, cy: 2, width: 3, height: 1});
    assert.doesNotThrow(function () {
      arc.validateAttributes();
    });
  });

  it('toRaphaelObject adds type and calculates path', function () {
    var arc, raphaelObj;
    arc = new Arc({cx: 2, cy: 2, width: 2, height: 2});

    arc.calculatePointOnEclipse = sinon.stub();
    arc.calculatePointOnEclipse.onFirstCall().returns({x: 1, y: 2});
    arc.calculatePointOnEclipse.onSecondCall().returns({x: 2, y: 3});

    raphaelObj = arc.toRaphaelObject();

    assert.deepEqual(raphaelObj, {
      type: 'path',
      path: 'M1,2A1,1 0 0,1 2,3'
    });
  });

  describe('helpers', function () {
    var arc;

    beforeEach(function () {
      arc = new Arc({});
    });

    it('converts degrees to radians correctly', function () {
      // sin(30) == 0.5
      var radians;
      radians = Math.sin(arc.degreesToRadians(30)).toPrecision(2);

      assert.equal(radians, 0.5);
    });

    it('calculates the point correctly when the start point is 0', function () {
      var point;

      point = arc.calculatePointOnEclipse(2, 2, 1, 1, 0);

      assert.deepEqual(point, {x: 1, y: 2});
    });

    it('calculates the point correctly when the start point is 30', function () {
      var point;

      point = arc.calculatePointOnEclipse(2, 2, 1, 1, 30);

      // cos(30) == 0.866025
      // sin(30) == 0.5
      assert.equal(point.x.toPrecision(4), 2 - 0.866);
      assert.equal(point.y, 2.5);
    });

    it('calculates the point correctly when the start point is 45', function () {
      var point;

      point = arc.calculatePointOnEclipse(2, 2, 1, 1, 45);

      // cos(45) == sin(45) == 0.7071
      assert.equal(point.x.toPrecision(5), 2 - 0.7071);
      assert.equal(point.y.toPrecision(5), 2 + 0.7071);
    });

    it('calculates the point correctly when the start point is 60', function () {
      var point;

      point = arc.calculatePointOnEclipse(2, 2, 1, 1, 60);

      // cos(45) == 0.5
      // sin(45) == 0.866025
      assert.equal(point.x, 1.5);
      assert.equal(point.y.toPrecision(4), 2 + 0.866);
    });
  });
});