text: 
  var expect = require('expect.js');
  var matrixFillColNum = require('../src/matrix-fill-column-number');
  var createMatrix = require('../src/create-matrix');
  
  describe('matrixFillColNum', function() {
    it('is a function', function() {
      expect(matrixFillColNum).to.be.a('function');
    });
    
    it('returns an array', function() {
      var result = matrixFillColNum(createMatrix(5,2));
      expect(result).to.be.an('array');
    });
    
    it('cells contain column number', function() {
      var result = matrixFillColNum(createMatrix(5,2));
      expect(result[2][0]).to.be(0);
      expect(result[4][1]).to.be(1);
    });
  
  });