text: // test mod
  var assert = require('assert'),
      approx = require('../../../tools/approx'),
      math = require('../../../index')(),
      bignumber = math.bignumber,
      matrix = math.matrix,
      range = math.range,
      mod = math.mod;
  
  describe('mod', function() {
    it('should calculate the modulus of booleans correctly', function () {
      assert.equal(mod(true, true), 0);
      assert.equal(mod(false, true), 0);
      assert.equal(mod(true, false), 1);
      assert.equal(mod(false, false), 0);
    });
  
    it('should calculate the modulus of two numbers', function() {
      assert.equal(mod(1, 1), 0);
      assert.equal(mod(0, 1), 0);
      assert.equal(mod(1, 0), 1);
      assert.equal(mod(0, 0), 0);
  
      approx.equal(mod(7, 2), 1);
      approx.equal(mod(9, 3), 0);
      approx.equal(mod(10, 4), 2);
      approx.equal(mod(-10, 4), 2);
      approx.equal(mod(8.2, 3), 2.2);
      approx.equal(mod(4, 1.5), 1);
      approx.equal(mod(0, 3), 0);
    });
  
    it('should throw an error if the modulus is negative', function() {
      assert.throws(function () {mod(10, -4)});
    });
  
    it('should throw an error if used with wrong number of arguments', function() {
      assert.throws(function () {mod(1)}, math.error.ArgumentsError);
      assert.throws(function () {mod(1,2,3)}, math.error.ArgumentsError);
    });
  
    it('should calculate the modulus of bignumbers', function() {
      assert.deepEqual(mod(bignumber(7), bignumber(2)), bignumber(1));
      assert.deepEqual(mod(bignumber(7), bignumber(2)), bignumber(1));
      assert.deepEqual(mod(bignumber(8), bignumber(3)).valueOf(), bignumber(2).valueOf());
    });
  
    it.skip('should calculate the modulus of bignumbers for fractions', function () {
      assert.deepEqual(mod(bignumber(7).div(3), bignumber(1).div(3)), bignumber(0));
    });
  
    it.skip('should calculate the modulus of bignumbers for negative values', function () {
      assert.deepEqual(mod(bignumber(-10), bignumber(4)), bignumber(2));
    });
  
    it('should calculate the modulus of mixed numbers and bignumbers', function() {
      assert.deepEqual(mod(bignumber(7), 2), bignumber(1));
      assert.deepEqual(mod(8, bignumber(3)), bignumber(2));
  
      approx.equal(mod(7/3, bignumber(2)), 1/3);
      approx.equal(mod(7/3, 1/3), 0);
      approx.equal(mod(bignumber(7).div(3), 1/3), 0);
    });
  
    it('should calculate the modulus of mixed booleans and bignumbers', function() {
      assert.deepEqual(mod(bignumber(7), true), bignumber(0));
      assert.deepEqual(mod(true, bignumber(3)), bignumber(1));
    });
  
    it('should throw an error if used on complex numbers', function() {
      assert.throws(function () {mod(math.complex(1,2), 3)}, TypeError);
      assert.throws(function () {mod(3, math.complex(1,2))}, TypeError);
      assert.throws(function () {mod(bignumber(3), math.complex(1,2))}, TypeError);
    });
  
    it('should an throw an error if used on a string', function() {
      assert.throws(function () {mod('string', 3)}, TypeError);
      assert.throws(function () {mod(5, 'string')}, TypeError);
    });
  
    it('should perform element-wise modulus on a matrix', function() {
      approx.deepEqual(mod([-4,-3,-2,-1,0,1,2,3,4], 3), [2,0,1,2,0,1,2,0,1]);
      approx.deepEqual(mod(matrix([-4,-3,-2,-1,0,1,2,3,4]), 3), matrix([2,0,1,2,0,1,2,0,1]));
    });
  
  });