openlayers/test/node/ol/math.test.js

import expect from '../expect.js';
import {
  clamp,
  cosh,
  lerp,
  log2,
  modulo,
  solveLinearSystem,
  toDegrees,
  toRadians,
} from '../../../src/ol/math.js';

describe('ol/math.js', () => {
  describe('clamp', function () {
    it('returns the correct value at -Infinity', function () {
      expect(clamp(-Infinity, 10, 20)).to.eql(10);
    });

    it('returns the correct value at min', function () {
      expect(clamp(10, 10, 20)).to.eql(10);
    });

    it('returns the correct value at mid point', function () {
      expect(clamp(15, 10, 20)).to.eql(15);
    });

    it('returns the correct value at max', function () {
      expect(clamp(20, 10, 20)).to.eql(20);
    });

    it('returns the correct value at Infinity', function () {
      expect(clamp(Infinity, 10, 20)).to.eql(20);
    });
  });

  describe('cosh', function () {
    it('returns the correct value at -Infinity', function () {
      expect(cosh(-Infinity)).to.eql(Infinity);
    });

    it('returns the correct value at -1', function () {
      expect(cosh(-1)).to.roughlyEqual(1.5430806348152437, 1e-9);
    });

    it('returns the correct value at 0', function () {
      expect(cosh(0)).to.eql(1);
    });

    it('returns the correct value at 1', function () {
      expect(cosh(1)).to.roughlyEqual(1.5430806348152437, 1e-9);
    });

    it('returns the correct value at Infinity', function () {
      expect(cosh(Infinity)).to.eql(Infinity);
    });
  });

  describe('log2', function () {
    it('returns the correct value at Infinity', function () {
      expect(log2(Infinity)).to.eql(Infinity);
    });

    it('returns the correct value at 3', function () {
      expect(log2(3)).to.roughlyEqual(1.584962500721156, 1e-9);
    });

    it('returns the correct value at 2', function () {
      expect(log2(2)).to.eql(1);
    });

    it('returns the correct value at 1', function () {
      expect(log2(1)).to.eql(0);
    });

    it('returns the correct value at 0', function () {
      expect(log2(0)).to.eql(-Infinity);
    });

    it('returns the correct value at -1', function () {
      expect(log2(-1).toString()).to.eql('NaN');
    });
  });

  describe('solveLinearSystem', function () {
    it('calculates correctly', function () {
      const result = solveLinearSystem([
        [2, 1, 3, 1],
        [2, 6, 8, 3],
        [6, 8, 18, 5],
      ]);
      expect(result[0]).to.roughlyEqual(0.3, 1e-9);
      expect(result[1]).to.roughlyEqual(0.4, 1e-9);
      expect(result[2]).to.roughlyEqual(0, 1e-9);
    });

    it('can handle singular matrix', function () {
      const result = solveLinearSystem([
        [2, 1, 3, 1],
        [2, 6, 8, 3],
        [2, 1, 3, 1],
      ]);
      expect(result).to.be(null);
    });
  });

  describe('toDegrees', function () {
    it('returns the correct value at -π', function () {
      expect(toDegrees(-Math.PI)).to.be(-180);
    });
    it('returns the correct value at 0', function () {
      expect(toDegrees(0)).to.be(0);
    });
    it('returns the correct value at π', function () {
      expect(toDegrees(Math.PI)).to.be(180);
    });
  });

  describe('toRadians', function () {
    it('returns the correct value at -180', function () {
      expect(toRadians(-180)).to.be(-Math.PI);
    });
    it('returns the correct value at 0', function () {
      expect(toRadians(0)).to.be(0);
    });
    it('returns the correct value at 180', function () {
      expect(toRadians(180)).to.be(Math.PI);
    });
  });

  describe('modulo', function () {
    it('256 / 8 returns 0', function () {
      expect(modulo(256, 8)).to.be(0);
    });
    it('positive and positive returns a positive ', function () {
      expect(modulo(7, 8)).to.be(7);
    });
    it('same Dividend and Divisor returns 0', function () {
      expect(modulo(4, 4)).to.be(0);
    });
    it('negative and positive returns positive', function () {
      expect(modulo(-3, 4)).to.be(1);
    });
    it('negative and negative returns negative', function () {
      expect(modulo(-4, -5)).to.be(-4);
      expect(modulo(-3, -4)).to.be(-3);
    });
    it('positive and negative returns negative', function () {
      expect(modulo(3, -4)).to.be(-1);
      expect(modulo(1, -5)).to.be(-4);
      expect(modulo(6, -5)).to.be(-4);
    });
  });

  describe('lerp', function () {
    it('correctly interpolated numbers', function () {
      expect(lerp(0, 0, 0)).to.be(0);
      expect(lerp(0, 1, 0)).to.be(0);
      expect(lerp(1, 11, 5)).to.be(51);
    });
    it('correctly interpolates floats', function () {
      expect(lerp(0, 1, 0.5)).to.be(0.5);
      expect(lerp(0.25, 0.75, 0.5)).to.be(0.5);
    });
  });
});