text: var assert = require('assert'),
      math = require('../../index')(),
      index = math.index,
      Matrix = require('../../lib/type/Matrix');
  
  describe('matrix', function() {
  
    describe('constructor', function() {
  
      it('should build an empty if called with no argument', function() {
        var m = new Matrix();
        assert.deepEqual(m.toArray(), []);
      });
  
      it('should create a matrix from an other matrix', function () {
        var m = new Matrix([1,2,3]);
        var n = new Matrix(m);
  
        m.resize([0]); // empty matrix m to ensure n is a clone
  
        assert.deepEqual(n, new Matrix([1,2,3]));
      });
  
      it('should create a matrix an array containing matrices', function () {
        var m = new Matrix([new Matrix([1,2]), new Matrix([3, 4])]);
  
        assert.deepEqual(m, new Matrix([[1,2],[3, 4]]));
      });
  
      it('should throw an error when called without new keyword', function () {
        assert.throws(function () {Matrix()}, /Constructor must be called with the new operator/);
      });
  
    });
  
    describe('size', function() {
  
      it('should return the expected size', function() {
        assert.deepEqual(new Matrix().size(), [0]);
        assert.deepEqual(new Matrix([[23]]).size(), [1,1]);
        assert.deepEqual(new Matrix([[1,2,3],[4,5,6]]).size(), [2,3]);
        assert.deepEqual(new Matrix([1,2,3]).size(), [3]);
        assert.deepEqual(new Matrix([[1],[2],[3]]).size(), [3,1]);
        assert.deepEqual(new Matrix([[[1],[2],[3]]]).size(), [1,3,1]);
        assert.deepEqual(new Matrix([[[3]]]).size(), [1,1,1]);
        assert.deepEqual(new Matrix([[]]).size(), [1,0]);
      });
  
    });
  
    it('toString', function() {
      assert.equal(new Matrix([[1,2],[3,4]]).toString(), '[[1, 2], [3, 4]]');
      assert.equal(new Matrix([[1,2],[3,1/3]]).toString(), '[[1, 2], [3, 0.3333333333333333]]');
    });
  
    it('format', function() {
      assert.equal(new Matrix([[1,2],[3,1/3]]).format(), '[[1, 2], [3, 0.3333333333333333]]');
      assert.equal(new Matrix([[1,2],[3,1/3]]).format(3), '[[1, 2], [3, 0.333]]');
      assert.equal(new Matrix([[1,2],[3,1/3]]).format(4), '[[1, 2], [3, 0.3333]]');
    });
  
    describe('resize', function() {
  
      it('should resize the matrix correctly', function() {
        var m = new Matrix([[1,2,3],[4,5,6]]);
        m.resize([2,4]);
        assert.deepEqual(m.valueOf(), [arr(1,2,3,uninit),arr(4,5,6,uninit)]);
  
        m.resize([1,2]);
        assert.deepEqual(m.valueOf(), [[1,2]]);
  
        m.resize([1,2,2], 8);
        assert.deepEqual(m.valueOf(), [[[1,2],[8,8]]]);
  
        m.resize([2,3], 9);
        assert.deepEqual(m.valueOf(), [[1, 2, 9], [8, 8, 9]]);
  
        m = new Matrix();
        m.resize([3,3,3], 6);
        assert.deepEqual(m.valueOf(), [
          [[6,6,6],[6,6,6],[6,6,6]],
          [[6,6,6],[6,6,6],[6,6,6]],
          [[6,6,6],[6,6,6],[6,6,6]]
        ]);
  
        m.resize([2,2]);
        assert.deepEqual(m.valueOf(), [[6,6],[6,6]]);
  
        m.resize([0]);
        assert.deepEqual(m.valueOf(), []);
      });
  
    });
  
    describe('get', function() {
      var m = new Matrix([[0, 1], [2, 3]]);
  
      it('should get a value from the matrix', function() {
        assert.equal(m.get([1,0]), 2);
        assert.equal(m.get([0,1]), 1);
      });
  
      it('should throw an error when getting a value out of range', function() {
        assert.throws(function () {m.get([3,0])});
        assert.throws(function () {m.get([1,5])});
        assert.throws(function () {m.get([1])});
        assert.throws(function () {m.get([])});
      });
  
      it('should throw an error in case of dimension mismatch', function() {
        assert.throws(function () {m.get([0,2,0,2,0,2])}, /Dimension mismatch/);
      });
  
      it('should throw an error when getting a value given a invalid index', function() {
        assert.throws(function () {m.get([1.2, 2])});
        assert.throws(function () {m.get([1,-2])});
        assert.throws(function () {m.get(1,1)});
        assert.throws(function () {m.get(math.index(1,1))});
        assert.throws(function () {m.get([[1,1]])});
      });
  
    });
  
    describe('set', function() {
      it('should set a value in a matrix', function() {
        var m = new Matrix([[0, 0], [0, 0]]);
        m.set([1,0], 5);
        assert.deepEqual(m, new Matrix([[0, 0], [5, 0]]));
  
        m.set([0, 2], 4);
        assert.deepEqual(m, new Matrix([[0, 0, 4], arr(5, 0, uninit)]));
  
        m.set([1,0,0], 3);
        assert.deepEqual(m, new Matrix([
          [[0, 0, 4], arr(5, 0, uninit)],
          [arr(3, uninit, uninit), arr(uninit, uninit, uninit)]
        ]));
      });
  
      it('should set a value in a matrix with defaultValue for new elements', function() {
        var m = new Matrix();
        var defaultValue = 0;
        m.set([2], 4, defaultValue);
        assert.deepEqual(m, new Matrix([0, 0, 4]));
      });
  
      it('should throw an error when setting a value given a invalid index', function() {
        var m = new Matrix([[0, 0], [0, 0]]);
        assert.throws(function() {m.set([2.5,0], 5)});
        assert.throws(function() {m.set([1], 5)});
        assert.throws(function() {m.set([-1, 1], 5)});
        assert.throws(function() {m.set(math.index([0,0]), 5)});
      });
  
    });
  
    // TODO: replace all assert.deepEqual(a.valueOf(), [...]) with assert.deepEqual(a, new Matrix([...]))
  
    describe('get subset', function() {
  
      it('should get the right subset of the matrix', function() {
        var m;
  
        // get 1-dimensional
        m = new Matrix(math.range(0,10));
        assert.deepEqual(m.size(), [10]);
        assert.deepEqual(m.subset(index([2,5])).valueOf(), [2,3,4]);
  
        // get 2-dimensional
        m = new Matrix([[1,2,3],[4,5,6],[7,8,9]]);
        assert.deepEqual(m.size(), [3,3]);
        assert.deepEqual(m.subset(index(1,1)), 5);
        assert.deepEqual(m.subset(index([0,2],[0,2])).valueOf(), [[1,2],[4,5]]);
        assert.deepEqual(m.subset(index(1, [1,3])).valueOf(), [5,6]);
        assert.deepEqual(m.subset(index(0, [1,3])).valueOf(), [2,3]);
        assert.deepEqual(m.subset(index([1,3], 1)).valueOf(), [[5],[8]]);
        assert.deepEqual(m.subset(index([1,3], 2)).valueOf(), [[6],[9]]);
  
        // get n-dimensional
        m = new Matrix([[[1,2],[3,4]], [[5,6],[7,8]]]);
        assert.deepEqual(m.size(), [2,2,2]);
        assert.deepEqual(m.subset(index([0,2],[0,2],[0,2])).valueOf(), m.valueOf());
        assert.deepEqual(m.subset(index(0,0,0)), 1);
        assert.deepEqual(m.subset(index(1,1,1)).valueOf(), 8);
        assert.deepEqual(m.subset(index(1,1,[0,2])).valueOf(), [7,8]);
        assert.deepEqual(m.subset(index(1,[0,2],1)).valueOf(), [[6],[8]]);
      });
  
      it('should throw an error if the given subset is invalid', function() {
        var m = new Matrix();
        assert.throws(function () { m.subset([-1]); });
  
        m = new Matrix([[1,2,3],[4,5,6]]);
        assert.throws(function () { m.subset([1,2,3]); });
        assert.throws(function () { m.subset([3,0]); });
        assert.throws(function () { m.subset([1]); });
      });
  
      it('should throw an error in case of wrong number of arguments', function() {
        var m = new Matrix();
        assert.throws(function () { m.subset();}, /Wrong number of arguments/);
        assert.throws(function () { m.subset(1,2,3,4); }, /Wrong number of arguments/);
      });
  
      it('should throw an error in case of dimension mismatch', function() {
        var m = new Matrix([[1,2,3],[4,5,6]]);
        assert.throws(function () {m.subset(index([0,2]))}, /Dimension mismatch/);
      });
  
    });
  
    describe('set subset', function() {
  
      it('should set the given subset', function() {
        // set 1-dimensional
        var m = new Matrix(math.range(0,7));
        m.subset(index([2,4]), [20,30]);
        assert.deepEqual(m, new Matrix([0,1,20,30,4,5,6]));
        m.subset(index(4), 40);
        assert.deepEqual(m, new Matrix([0,1,20,30,40,5,6]));
  
        // set 2-dimensional
        m = new Matrix();
        m.resize([3,3]);
        assert.deepEqual(m, new Matrix([
          arr(uninit, uninit, uninit),
          arr(uninit, uninit, uninit),
          arr(uninit, uninit, uninit)
        ]));
        m.subset(index([1,3], [1,3]), [[1,2],[3,4]]);
        assert.deepEqual(m, new Matrix([
          arr(uninit, uninit, uninit),
          arr(uninit, 1,2),
          arr(uninit, 3,4)]));
        m.subset(index(0, [0,3]), [5,6,7]);  // unsqueezes the submatrix
        assert.deepEqual(m, new Matrix([[5,6,7],arr(uninit,1,2),arr(uninit,3,4)]));
      });
  
      it('should set the given subset with defaultValue for new elements', function() {
        // multiple values
        var m = new Matrix();
        var defaultValue = 0;
        m.subset(index([3,5]), [3, 4], defaultValue);
        assert.deepEqual(m, new Matrix([0, 0, 0, 3, 4]));
  
        defaultValue = 1;
        m.subset(index(1, [3,5]), [5, 6], defaultValue);
        assert.deepEqual(m, new Matrix([
          [0, 0, 0, 3, 4],
          [1, 1, 1, 5, 6]
        ]));
  
        defaultValue = 2;
        m.subset(index(2, [3,5]), [7, 8], defaultValue);
        assert.deepEqual(m, new Matrix([
          [0, 0, 0, 3, 4],
          [1, 1, 1, 5, 6],
          [2, 2, 2, 7, 8]
        ]));
  
        // a single value
        var i = math.matrix();
        defaultValue = 0;
        i.subset(math.index(2, 1), 6, defaultValue);
        assert.deepEqual(i, new Matrix([[0, 0], [0, 0], [0, 6]]));
      });
  
      it('should resize the matrix if the replacement subset is different size than selected subset', function() {
        // set 2-dimensional with resize
        var m = new Matrix([[123]]);
        m.subset(index([1,3], [1,3]), [[1,2],[3,4]]);
        assert.deepEqual(m, new Matrix([arr(123,uninit, uninit),arr(uninit,1,2),arr(uninit,3,4)]));
  
        // set resize dimensions
        m = new Matrix([123]);
        assert.deepEqual(m.size(), [1]);
  
        m.subset(index([1,3], [1,3]), [[1,2],[3,4]]);
        assert.deepEqual(m, new Matrix([arr(123,uninit,uninit),arr(uninit,1,2),arr(uninit,3,4)]));
  
        m.subset(index([0,2], [0,2]), [[55,55],[55,55]]);
        assert.deepEqual(m, new Matrix([arr(55,55,uninit),[55,55,2],arr(uninit,3,4)]));
  
        m = new Matrix();
        m.subset(index([1,3], [1,3], [1,3]), [[[1,2],[3,4]],[[5,6],[7,8]]]);
        var res = new Matrix([
          [
            arr(uninit, uninit, uninit),
            arr(uninit, uninit, uninit),
            arr(uninit, uninit, uninit)
          ],
          [
            arr(uninit, uninit, uninit),
            arr(uninit, 1, 2),
            arr(uninit, 3, 4)
          ],
          [
            arr(uninit, uninit, uninit),
            arr(uninit, 5, 6),
            arr(uninit, 7, 8)
          ]
        ]);
        assert.deepEqual(m, res);
      });
  
      it ('should throw an error in case of wrong type of index', function () {
        assert.throws(function () {new Matrix().subset('no index', 2)}, /Invalid index/)
      });
  
      it ('should throw an error in case of wrong size of submatrix', function () {
        assert.throws(function () {new Matrix().subset(index(0), [2,3])}, /Scalar expected/)
      });
  
      it('should throw an error in case of dimension mismatch', function() {
        var m = new Matrix([[1,2,3],[4,5,6]]);
        assert.throws(function () {m.subset(index([0,2]), [100,100])}, /Dimension mismatch/);
        assert.throws(function () {m.subset(index([0,2], [0,2]), [100,100])}, /Dimension mismatch/);
      });
  
    });
  
    describe('map', function() {
  
      it('should apply the given function to all elements in the matrix', function() {
        var m, m2;
  
        m = new Matrix([
          [[1,2],[3,4]],
          [[5,6],[7,8]],
          [[9,10],[11,12]],
          [[13,14],[15,16]]
        ]);
        m2 = m.map(function (value) { return value * 2; });
        assert.deepEqual(m2.valueOf(), [
          [[2,4],[6,8]],
          [[10,12],[14,16]],
          [[18,20],[22,24]],
          [[26,28],[30,32]]
        ]);
  
        m = new Matrix([1]);
        m2 = m.map(function (value) { return value * 2; });
        assert.deepEqual(m2.valueOf(), [2]);
  
        m = new Matrix([1,2,3]);
        m2 = m.map(function (value) { return value * 2; });
        assert.deepEqual(m2.valueOf(), [2,4,6]);
      });
  
      it('should work on empty matrices', function() {
        var m, m2;
        m = new Matrix([]);
        m2 = m.map(function (value) { return value * 2; });
        assert.deepEqual(m2.valueOf(), []);
      });
  
      it('should invoke callback with parameters value, index, obj', function() {
        var m = new Matrix([[1,2,3], [4,5,6]]);
  
        assert.deepEqual(m.map(function (value, index, obj) {
          return math.clone([value, index, obj === m]);
        }).valueOf(), [
          [
            [1, [0, 0], true ],
            [2, [0, 1], true ],
            [3, [0, 2], true ]
          ],
          [
            [4, [1, 0], true ],
            [5, [1, 1], true ],
            [6, [1, 2], true ]
          ]
        ]);
  
      });
  
    });
  
    describe('forEach', function() {
  
      it('should run on all elements of the matrix, last dimension first', function() {
        var m, output;
  
        m = new Matrix([
          [[1,2],[3,4]],
          [[5,6],[7,8]],
          [[9,10],[11,12]],
          [[13,14],[15,16]]
        ]);
        output = [];
        m.forEach(function (value) { output.push(value); });
        assert.deepEqual(output, [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]);
  
        m = new Matrix([1]);
        output = [];
        m.forEach(function (value) { output.push(value); });
        assert.deepEqual(output, [1]);
  
        m = new Matrix([1,2,3]);
        output = [];
        m.forEach(function (value) { output.push(value); });
        assert.deepEqual(output, [1,2,3]);
      });
  
      it('should work on empty matrices', function() {
        m = new Matrix([]);
        output = [];
        m.forEach(function (value) { output.push(value); });
        assert.deepEqual(output, []);
      });
  
      it('should invoke callback with parameters value, index, obj', function() {
        var m = new Matrix([[1,2,3], [4,5,6]]);
  
        var output = [];
        m.forEach(function (value, index, obj) {
          output.push(math.clone([value, index, obj === m]));
        });
        assert.deepEqual(output, [
          [1, [0, 0], true ],
          [2, [0, 1], true ],
          [3, [0, 2], true ],
          [4, [1, 0], true ],
          [5, [1, 1], true ],
          [6, [1, 2], true ]
        ]);
      });
  
    });
  
    describe('clone', function() {
  
      it('should clone the matrix properly', function() {
        var m = new Matrix([[1,2,3], [4,5,6]]);
        var m4 = m.clone();
        assert.deepEqual(m4.size(), [2,3]);
        assert.deepEqual(m4.valueOf(), [[1,2,3], [4,5,6]]);
      });
  
    });
  
  });
  
  // TODO: extensively test Matrix
  
  
  /**
   * Helper function to create an Array containing uninitialized values
   * Example: arr(uninit, uninit, 2);    // [ , , 2 ]
   */
  var uninit = {};
  function arr() {
    var array = [];
    array.length = arguments.length;
    for (var i = 0; i < arguments.length; i++) {
      var value = arguments[i];
      if (value !== uninit) {
        array[i] = value;
      }
    }
    return array;
  }
  