mathjs/test/function/matrix/subset.test.js

var assert = require('assert'),
    error = require('../../../lib/error/index'),
    math = require('../../../index'),
    subset = math.subset,
    matrix = math.matrix,
    range = math.range,
    index = math.index;

describe('subset', function() {

  var a = [[1,2], [3,4]];
  var b = math.matrix(a);

  it('should get the right subset of an array', function() {
    assert.deepEqual(subset(a, index([0,2], 1)), [[2],[4]]);
    assert.deepEqual(subset(a, index(1,0)), 3);
  });

  it('should throw an error if trying to access an invalid subset of an array', function() {
    assert.throws(function () {subset(a, index(6, 0))}, RangeError);
    assert.throws(function () {subset(a, index(1))}, RangeError);
    assert.throws(function () {subset(a, index(1,0,0))}, RangeError);
    assert.throws(function () {subset(a, index(1.3, 0))}, TypeError);
  });

  it('should get the right subset of a matrix', function() {
    assert.deepEqual(subset(b, index([0,2], 1)), matrix([[2],[4]]));
    assert.deepEqual(subset(b, index(1, 0)), 3);
  });

  it('should get a subset of a matrix returning a null or undefined value', function() {
    assert.deepEqual(subset([0], index(0)), 0);
    assert.deepEqual(subset([null], index(0)), null);
    assert.deepEqual(subset([undefined], index(0)), undefined);

    assert.deepEqual(subset([null, undefined], index([0,2])), [null, undefined]);
  });

  it('should throw an error if trying to access an invalid subset of a matrix', function() {
    assert.throws(function () {subset(b, index(6, 0))}, RangeError);
    assert.throws(function () {subset(b, index(1))}, RangeError);
    assert.throws(function () {subset(b, index(1,0,0))}, RangeError);
    assert.throws(function () {subset(b, index(1.3, 0))}, TypeError);
  });

  var d = [[1,2], [3,4]];
  var g  = matrix([[1,2], [3,4]]);

  // TODO: test getting subset of an array and matrix

  it('should set the right subset of an array', function() {
    assert.deepEqual(d, [[1,2], [3,4]]);
    assert.deepEqual(subset(d, index([0,2], 1), [[-2],[-4]]), [[1,-2], [3,-4]]);
    assert.deepEqual(d, [[1,2], [3,4]]);
    assert.deepEqual(subset(d, index(2, [0,2]), [[5,6]]), [[1,2], [3,4], [5,6]]);
    assert.deepEqual(d, [[1,2], [3,4]]);
    assert.deepEqual(subset(d, index(0,0), 123), [[123,2], [3,4]]);
  });

  it('should set a subset of an array with uninitialized default value', function() {
    var a = [];
    assert.deepEqual(subset(a, index(2), 1), [0,0,1]);
    assert.deepEqual(subset(a, index(2), 1, math.uninitialized), arr(uninit, uninit,1));
  });

  it('should throw an error if setting the subset of an array with an invalid replacement', function() {
    assert.throws(function () {subset(d, index(1), 123)}, RangeError);
    assert.throws(function () {subset(d, index(1.3,0), 123)}, TypeError);
  });

  it('should set the right subset of a matrix', function() {
    assert.deepEqual(g, matrix([[1,2], [3,4]]));
    assert.deepEqual(subset(g, index([0,2], 1), [[-2],[-4]]), matrix([[1,-2], [3,-4]]));
    assert.deepEqual(g, matrix([[1,2], [3,4]]));
    assert.deepEqual(subset(g, index(2, [0,2]), [[5,6]]), matrix([[1,2], [3,4], [5,6]]));
  });

  it('should throw an error if setting the subset of a matrix with an invalid replacement', function() {
    assert.throws(function () {subset(d, index(1), 123)}, RangeError);
    assert.throws(function () {subset(d, index(1.3,0), 123)}, TypeError);
  });

  describe('string', function () {

    it('should get the right subset of a string', function() {
      assert.deepEqual(subset('hello', index(1)), 'e');
      assert.deepEqual(subset('hello', index([4,-1,-1])), 'olleh');
    });

    it('should throw an error if trying to access an invalid subset of a string', function() {
      assert.throws(function () {subset('hello', 1)}, TypeError);
      assert.throws(function () {subset('hello', index([6]))}, SyntaxError);
      assert.throws(function () {subset('hello', index([-2]))}, SyntaxError);
      assert.throws(function () {subset('hello', index([1.3]))}, TypeError);
    });

    it('should set the right subset of a string', function() {
      var j = 'hello';
      assert.deepEqual(subset(j, index(0), 'H'), 'Hello');
      assert.deepEqual(j, 'hello');
      assert.deepEqual(subset(j, index(5), '!'), 'hello!');
      assert.deepEqual(j, 'hello');
      assert.deepEqual(subset(j, index([5,11]), ' world'), 'hello world');
      assert.deepEqual(j, 'hello');
    });

    it('should throw an error when index is out of range for a string', function() {
      assert.throws(function () {subset('hello', index(5))}, /Index out of range/);
      assert.throws(function () {subset('hello', index(-1))}, /Index out of range/);
    });

    it('should set the right subset of a string with resizing', function() {
      var j = '';
      var defaultValue = 'i';
      assert.deepEqual(subset(j, index(5), '!', defaultValue), 'iiiii!');
    });

    it('should throw an error if setting the subset of a string with an invalid replacement', function() {
      assert.throws(function () {subset('hello', index([1,2]), '1234')}, RangeError);
      assert.throws(function () {subset('hello', index(1,2), 'a')}, RangeError);
    });

    it('should throw an error if in case of dimensions mismatch', function() {
      assert.throws(function () {subset('hello', index(1,2))}, /Dimension mismatch/);
      assert.throws(function () {subset('hello', index(1,2), 'a')}, /Dimension mismatch/);
    });

    it('should throw an error if in case of a default value with length > 0', function() {
      assert.throws(function () {subset('hello', index(10), '!', 'foo')}, /Single character expected as defaultValue/);
    });

    it('should throw an error if in case of an invalid index type', function() {
      assert.throws(function () {subset('hello', 2)}, /Index expected/);
      assert.throws(function () {subset('hello', 2, 'A')}, /Index expected/);
    });

  });

  it('should throw an error in case of invalid number of arguments', function() {
    assert.throws(function () {subset()}, error.ArgumentsError);
    assert.throws(function () {subset(d)}, error.ArgumentsError);
    assert.throws(function () {subset(d, index(0,0), 1, 0, 5)}, error.ArgumentsError);
  });

  it('should throw an error in case of invalid type of arguments', function() {
    assert.throws(function () {subset(new Date(), index(0))}, math.error.UnsupportedTypeError);
    assert.throws(function () {subset(new Date(), index(0), 2)}, math.error.UnsupportedTypeError);
    assert.throws(function () {subset([1,2], [0])}, math.error.TypeError);
  });

  it('should LaTeX subset', function () {
    var expression = math.parse('subset([1],index(0,0))');
    assert.equal(expression.toTex(), '\\mathrm{subset}\\left({\\begin{bmatrix}1\\\\\\end{bmatrix}},{\\mathrm{index}\\left({0},{0}\\right)}\\right)');
  });
});

/**
 * 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;
}